This work was supported by the National Research Foundation of Korea (NRF), grant no. 2014R1A4A1003712 (BRL Program), the Korea CCS R&amp;D Center (KCRC) grant funded by the Korea government (Ministry of Science, ICT &amp; Future Planning) (No. NRF-2014M1A8A1049303), an End-Run grant from KAIST funded by the Korea government in 2016 (Ministry of Science, ICT &amp; Future Planning) (N11160058), the Wearable Platform Materials Technology Center (WMC) (NR-2016R1A5A1009926), an National Research Foundation of Korea (NRF) Grant funded by the Korean Government (NRF-2017H1A2A1042006-Global Ph.D. Fellowship Program), a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP; Ministry of Science, ICT &amp; Future Planning) (NRF-2018R1C1B6002624), the Nano&#183;Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, and an ICT and Future Planning (2009-0082580) and NRF grant funded by the Korea government (MSIP; Ministry of Science, ICT &amp; Future Planning) (NRF-2018R1C1B6002624).

1. Synthesis of SnO2 Nanotubes by Electrospinning and Subsequent Heat Treatment17
<ol>
	<li>Prepare an electrospinning solution.
	<ol>
		<li>Dissolve 0.25 g of tin chloride dihydrate in a solvent mixture of 1.25 g of ethanol and 1.25 g of dimethylformamide (DMF) at room temperature (RT, 25 &#176;C).</li>
		<li>After stirring for 2 h, add 0.35 g of polyvinylpyrrolidone (PVP) to the electrospinning solution and stir the mixture for another 6 h.</li>
	</ol>
	</li>
	<li>Perform an electrospinning of the Sn precursor/PVP composite nanofibers.
	<ol>
		<li>When the electrospinning solution is well prepared, wash the rectangular, flexible stainless steel (30 x 20.5 cm) with deionized (DI) water and ethanol 2x - 5x and air-dry it at 60 &#176;C for 10 min.</li>
		<li>Transfer the electrospinning solution to a 10 mL syringe by blocking one side of the syringe and letting the electrospinning solution flow into the syringe.</li>
		<li>Connect a 25 G needle to the syringe. 
		NOTE: Other types of needles, such as 23 G and 17 G needles, can also be used. In this protocol, the 25 G needle is used as the standard needle.</li>
		<li>Fix the dried flexible stainless steel into the drummer with tape.</li>
		<li>Open the electrospinning controller software and enter the electrospinning parameters (flow rate: 5 - 20 &#181;L&#183;min-1, total amount of the solution: 3 - 15 mL) for the proper functioning of the electrospinning device. 
		NOTE: Here, the optimal flow rate is 10 &#181;L&#183;min-1 and the total amount of solution is 5 mL.</li>
		<li>Fix the syringe with the 25 G needle into the electrospinning device and, then, fix it with tape.</li>
		<li>Before electrospinning, press the syringe towards the collector until the electrospinning solution flows well through the 25 G needle. Then, connect the tip of the needle to the double-ended crocodile clips, which are also connected to the collector.</li>
		<li>Roll the roller (100 rpm) and initiate the electrospinning program software.</li>
		<li>Modulate the applied voltage by using a voltage bias (Figure 1a) between 10 - 25 kV to allow the electrojetting of the Taylor cones to operate the electrospinning process. 
		NOTE: Here, the optimal applied voltage is 16 kV.</li>
	</ol>
	</li>
	<li>Perform the calcination of the Sn precursor/PVP composite nanofibers.
	<ol>
		<li>When the electrospinning process is finished, scrape the as-spun nanofibers on the flexible stainless steel with a razor and transfer them into an alumina box.</li>
		<li>Insert the alumina box into the box furnace and set the heat treatment conditions for the box furnace: 600 &#176;C or 700 &#176;C for 1 h, with a ramping rate of 10 &#176;C&#183;min-1.</li>
		<li>After calcination, cool down the furnace to 50 &#176;C and, then, transfer the calcined samples (i.e., SnO2 nanotubes) to the vial glass (Figure 1b).</li>
	</ol>
	</li>
</ol>
2. Electrochemical Battery Cell Test
<ol>
	<li>Prepare the electrode. 
	NOTE: The electrode slurry is composed of 10 wt% binder, 10 wt% carbon black, and 80 wt% of active materials (in this case, SnO2 nanotubes). The amount of slurry and the composition of each ingredient in the slurry can be adjusted.
	<ol>
		<li>Cut the copper (Cu) foil into 10 cm width x 30 cm length and, using ethanol, fix it on a rectangular glass substrate (25 x 15 x 0.5 cm).</li>
		<li>Mix 0.02 g of carbon black, 0.027 g of polyacrylic acid (35 wt%), and 0.166 g of carboxymethyl cellulose (6 wt%) in a crucible. Add three to six drops of deionized (DI) water into the crucible to allow for a homogeneous mixing.</li>
		<li>Add 0.16 g of SnO2 nanotubes into the crucible. Then, add three to eight drops of DI water into the crucible to allow for a homogeneous mixing.</li>
		<li>Ground all the ingredients in the crucible for 30 min to ensure that the slurry is sufficiently viscous to be cast well on the Cu foil.</li>
		<li>When the electrode slurry is prepared well, place the slurry on the top side of the Cu foil on the glass substrate, and cast it evenly using a casting roller. 
		NOTE: Usually, the thickness of the slurry is 60 &#181;m but can be more or less.</li>
		<li>Air-dry the slurry-cast Cu foil at 60 &#176;C for 10 min and seal it inside the plastic bag prior to the battery cell assembly. 
		NOTE: The slurry-cast Cu foil can be seen in Figure 1c.</li>
	</ol>
	</li>
	<li>Assemble the battery cells.
	<ol>
		<li>Heat the convection oven to 150 &#176;C. Then, place the slurry-cast Cu foil into the oven.</li>
		<li>Fill the convection oven with vacuum by rotary pumps to dry the residual solvent in the slurry while avoiding the oxidation of the Cu foil.</li>
		<li>After heating the slurry-cast Cu foil at 150 &#176;C for 2 h, refill the convection oven with air by closing the vacuum line and opening the vent line in the rotary pump to open the chamber.</li>
		<li>Take the slurry-cast Cu foil out of the chamber and punch it with a circle puncher (punch diameter: 14 mm). Weigh the punched slurry-cast Cu foil and place it into the bottom battery cell.</li>
		<li>Use half a cell for the assembly of the battery cells. After placing the slurry-cast Cu foil into the bottom of the battery cell, transfer the samples to the antichamber of the glove box.</li>
		<li>Vacuum the antichamber for 30 min and, then, transfer the samples into the inside glove box.</li>
		<li>Assemble the battery cells in the following order: bottom battery cell, slurry-cast Cu foil, separator, gasket, spring, spacer, and top battery cell. Drop the electrolyte after the separator is put into the battery cell.</li>
		<li>Compress the battery cell into a complete battery cell by a compactor.Then, move the battery cells for electrochemical tests into the antichamber in the glove box and take the battery cells out of the glove box.</li>
		<li>Measure the open circuit voltage (OCV) by a digital multimeter and age the battery cell at RT for 1 - 2 d.</li>
	</ol>
	</li>
	<li>Test the electrochemical battery cell.
	<ol>
		<li>Calculate the weight of the active materials by subtracting the weight of Cu foil from that of the slurry-cast Cu foil and dividing it by the portion of the active material.</li>
		<li>Calculate the current at which the battery cell needs to be run by multiplying the current density (mA&#183;g-1) with the weight of the active material.</li>
		<li>Insert the electrochemical battery cells in the battery cell tester. Apply the current (corresponding to 0.05 A&#183;g-1 for the formation cycle and various current densities in the range of 0.1 A&#183;g-1 to 10.0 A&#183;g-1 for the cycle tests and rate capabilities) for each battery cell using the battery cell tester program.</li>
		<li>Apply different currents for each battery cell if it is tested at various current densities.</li>
	</ol>
	</li>
</ol>
3. Preparation of the Graphene Liquid Cell
<ol>
	<li>Synthesize graphene by chemical vapor deposition (CVD).
	<ol>
		<li>Cut Cu foil (purity: 99.9%, thickness: 0.0125 mm) with scissors into pieces with a dimension of 10 x 3 cm.</li>
		<li>Rinse the Cu foil from step 3.1.1 with isopropyl alcohol (IPA) to remove any dust or contaminants and treat it with 100 mL of 20 wt% phosphoric acid (H3PO4) for 20 min to remove native oxide on the surface of the Cu foil in a glass Petri dish. Then, place the Cu foil in DI water for another 10 min to fully rinse the remaining H3PO4.</li>
		<li>Move the Cu foil to the quartz tube (outer diameter: 40 mm, inner diameter: 36 mm) of the CVD equipment.</li>
		<li>Run the rotary pump and wait until the vacuum level is under 2 x 10-3 Torr. Then, elevate the temperature to 150 &#176;C to fully remove the oxygen and moisture inside the quartz tube of the CVD.</li>
		<li>Elevate the temperature from RT to 1,000 &#176;C in 40 min with 10 sccm of H2 gas flow. Maintain the temperature of the chamber for another 40 min to anneal the Cu foil.</li>
		<li>Turn on 60 sccm of CH4 gas for 25 min. Cool down the CVD chamber to RT. Turn the CH4 and H2 gases off at 300 &#176;C.</li>
		<li>Take the Cu foil (Figure 2a) from the CVD chamber and keep it in a desiccator.</li>
	</ol>
	</li>
	<li>Transfer the graphene.
	<ol>
		<li>To remove the graphene on the backside of the Cu foil, conduct plasma etching by using a plasma cleaner with the following settings: a flow of Ar (of 100 sccm), time (of 60 s), power (of 30 W), and a base pressure (of 5.0 x 10-2 Torr).</li>
		<li>Cut the Cu foil with the graphene that was synthesized in step 3.1 to 3 x 3 mm with scissors. Place the Cu foil pieces between two slide glasses and press to make them flat. 
		NOTE: Four Cu foil pieces are placed together between two slide glasses.</li>
		<li>Place holey carbon Au grids (300 mesh, R2/2) on each piece of Cu foil (Figure 2b). Drop 20 &#181;L of IPA on the Au grid/Cu foil.</li>
		<li>Suction IPA with a micropipette tip that is connected to a rotary pump. After suctioning, dry the Au grid/Cu foil at 50 &#176;C for 5 min.</li>
		<li>Conduct the etching of the Cu foil in 10 mL of 0.1 M ammonium persulfate for 6 h in a 6 cm glass Petri dish (Figure 2c). 
		NOTE: Glass Petri dishes must be cleaned with IPA and DI water prior to use in order to avoid the contamination of the Si particles.</li>
		<li>Scoop the Au grids with a Pt loop and move it to a glass Petri dish filled with DI water at 50 &#176;C, in order to fully remove any remaining contaminants from the etchant16.</li>
		<li>Scoop the Au grids from the DI water and dry them for 6 h at RT and with atmospheric pressure.</li>
	</ol>
	</li>
	<li>Fabricate GLCs.
	<ol>
		<li>Prepare the electrolyte and nanotube mixture. Disperse 0.06 g of nanotube powder in 10 mL of electrolyte, which is composed of 1.3 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate (EC) and diethylene carbonate (DEC) (3:7 volume ratio) with 10 wt% of fluoroethylene carbonate (FEC). 
		NOTE: The composition of the electrolyte is the same as the one used in the electrochemical battery cell test. Various electrolytes can be employed in GLCs, such as 1 M LiPF6 dissolved in EC, DEC, and dimethyl carbonates (DMC) in a volumetric ratio of 1:1:1, 1 M of sodium hexafluorophosphate (NaPF6) dissolved in EC, 1 M of sodium perchlorate (NaClO4) dissolved in polyethylene carbonate (PC) with 5 wt% of FEC, 0.1 M of magnesium bis(trifluoromethanesulfonimide) (MgTFSI) in diglyme, and 1 M NaClO4 in PC.</li>
		<li>Move the graphene-transferred Au grids and electrolyte mixture into a glove box that is filled with Ar.</li>
		<li>Place one graphene-transferred Au grid on the bottom. Drop 20 &#181;L of electrolyte mixture on the bottom grid.</li>
		<li>Hold another graphene-transferred grid with a tweezer and place it on the top of the bottom grid. 
		NOTE: This procedure must be done quickly before the electrolyte has dried (Figure 2d).</li>
		<li>Dry the sample inside the glove box for 30 min, during which the liquid is spontaneously encapsulated between the two graphene sheets as it dries. 
		NOTE: The amount of entrapped liquid depends on how well the graphene has been transferred and how well the upper grid is placed.</li>
	</ol>
	</li>
</ol>
4. Performing Real-time TEM
<ol>
	<li>Load GLCs on a conventional single-tilt TEM holder.
	<ol>
		<li>Place the GLC sample (two attached graphene-transferred Au grids) on the single-tilt TEM holder.</li>
		<li>If the two grids are not stacked up perfectly, the GLC sample will not fit in the TEM holder. In that case, cut the edge of the Au grids with a razor blade.</li>
		<li>After the GLC sample is mounted on the TEM holder, put the TEM holder inside the TEM and carefully check the vacuum level.</li>
	</ol>
	</li>
	<li>Record real-time TEM videos.
	<ol>
		<li>Find the region where the SnO2 nanotube is encapsulated with liquid electrolyte. 
		NOTE: To find out whether liquid exists around the SnO2 nanotube, irradiate an electron beam for a few seconds. If some movement of liquid or the decomposition of an electrolyte is observed, it is highly likely that the area is encapsulated with liquid.</li>
		<li>Do alignment for TEM and set the electron beam dosage to initiate the reaction by adjusting the brightness knob. 
		NOTE: The suitable alignment for TEM includes user alignment, such as Z-height alignment, gun tilt/shift, beam tilt/shift, aperture alignment, and stigmation alignment. These procedures are better done in another area (right next to the region found in step 4.2.1) in order not to give any damage to the SnO2 nanotube and liquid electrolyte. The electron beam dose rate for initiating the lithiation is usually ~103e-/&#197;2&#183;s, but it may differ with every TEM instrument.</li>
		<li>Run the microscopy program and charge-coupled device (CCD) camera according to the manufacturer&#39;s instructions.</li>
		<li>Press the record button on the high definition (HD) video window and record the reaction occurring in the GLC sample.</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

There are critical steps within the protocol. First, the transfer of the graphene onto the TEM grid needs the researchers&#39; careful attention. It is important to handle the grids with tweezers and not damage any of grids, for instance by destroying the amorphous carbon membrane or bending the frame. These kinds of damages will result in a poor coverage of the graphene and affect the number of liquid pockets. In addition, placing the upper grid at the right position is critical. As described in the protocol, the top grid must be placed quickly before the liquid has dried. During this process, researchers may damage the upper grid or place it in the wrong position (i.e., not in the center of the bottom grid). Similar to any damages incurred during the transfer process, this will lower the yield of liquid cells. Thus, much practice with handling the TEM grids is needed to repeatedly fabricate GLCs.
It is important to make sure that the slurry-cast Cu foil has fully dried prior to the cell assembly. This is important because the presence of water can degrade the overall cell performance. Additionally, the slurry should be cast on the Cu foil uniformly, so that the loading amount of active material is similar. Moreover, it is important to find the right place for the TEM observation, where the liquid is completely sealed by the graphene sheets and enough liquid exists so that lithiation can continuously take place. Even though researchers followed the steps as they are demonstrated in the protocol, they will often observe incomplete reactions and depletion of liquid electrolyte around active materials. To find the right place for the TEM observation, the researchers should illuminate the electron beam for a few seconds and observe whether enough liquid exists for further reaction to occur.
The limitation of the GLC technique with observing lithiation is that the dynamics are possible only upon lithiation, not delithiation. Because lithiation inside GLCs is initiated by an electron beam and the reduction of surrounding electrolyte, the opposite oxidizing environment cannot be realized. This is a limitation compared to other in situ TEM techniques that can apply bias to the system, such as a scanning tunneling microscope (STM)-TEM holder or electrochemistry holders. Also, as two grids are attached and the upper grid is not removed in this experiment, aqueous solvents have less ability to stick two grids together and organic electrolyte is therefore preferred.
GLCs provide major advances in three different ways. 1) They provide high-resolution imaging in a liquid electrolyte that is hardly achievable in other in situ TEM platforms. 2) They do not require the purchase of an additional in situ TEM holder. 3) Also, various kinds of nanomaterials (such as nanosheet, nanoparticle, and nanofiber) can be visualized inside the liquid electrolyte.
GLCs can be used further to observe not only the dynamics of electrode materials upon lithiation but, also, sodiation (Na-ion batteries), magnesiation (Mg-ion batteries), potassiation (K-ion batteries), and zinc insertion (Zn-ion batteries). Furthermore, beyond the decomposition of various kinds of electrolytes, morphological changes of electrode materials can be visualized inside the GLC9,10. We expect that such information will provide valuable insights for engineers who are working on designing advanced secondary ion batteries.

Recently, the consumption of energy has constantly increased, as well as the importance of high-performance energy storage devices. To meet such a demand, the development of lithium-ion batteries that have a high energy density, durability, and safety is necessary1,2. In order to develop batteries with superior properties, a fundamental understanding of energy storage mechanisms during battery operation is essential3,4,5.
In situ transmission electron microscopy (TEM) provides rich insights as it can show both structural and chemical information during the operation of batteries3. Among many in situ TEM techniques, GLCs have been used for the observation of the lithiation dynamics of nanomaterials6,7,8,9,10,11,12. GLCs consist of a liquid pocket sealed by two graphene membranes, which provide an actual electrode/electrolyte interface by preventing the evaporation of the liquid inside the high vacuum in a TEM column6,7. The advantages of GLCs are that they allow a superior spatial resolution and high imaging contrast because they employ electron transparent monatomic-thick graphene as liquid sealing membrane13,14,15,16. Also, conventional TEM can be applicable to observe the battery reactions, without using expensive in situ TEM holders.
In this text, we introduce how the lithiation reaction can be observed with GLCs. Specifically, electron beam irradiation produces solvated electrons inside the liquid electrolyte, and they initiate lithiation by separating Li ions from solvent molecules.
GLCs also serve as the most optimal platform to allow the direct observation of nanomaterials with various morphologies, including nanoparticles6,9, nanotubes7,10,11, and even multidimensional materials12. Together with the ex situ TEM analysis of electrode materials after the actual electrochemical cell testing, it is possible that the GLC system presented here can be used to investigate the fundamental reaction mechanism.
With such advantages of GLCs and ex situ experiments, we introduce here detailed experiment methods for researchers who are willing to carry out similar GLC experiments. The protocols cover 1) the synthesis of tin (IV) oxide (SnO2) nanotubes as the typical one-dimensional nanostructured electrode materials, 2) the electrochemical battery cell test, 3) the preparation of GLC, and 4) the performance of a real-time TEM observation.

<table border="0" cellpadding="0" cellspacing="0" style="width:1340px;" width="1340">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="24">
			<td height="24" style="height:24px;width:373px;">Tin chloride dihyrate</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:200px;">CAS 10025-69-1</td>
			<td style="width:583px;">In a glass bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Ethanol</td>
			<td style="width:184px;">Merck</td>
			<td style="width:200px;">CAS 64-17-5</td>
			<td>In a glass bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Dimethylformamide</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:200px;">CAS 68-12-2</td>
			<td>In a glass bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Polyvinylpyrrolidone</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:200px;">CAS 9003-39-8</td>
			<td>In a plastic bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Cell tester</td>
			<td style="width:184px;">KOREA THERMO-TECH</td>
			<td style="width:200px;">Maccor Series 4000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Cell tester 2</td>
			<td style="width:184px;">WonaTech</td>
			<td style="width:200px;">WBCS4000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Sodium perchlorate</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:200px;">CAS 7601-89-0</td>
			<td>In a glass bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">25 gauge needle</td>
			<td style="width:184px;">Hwa-In Science Ltd.</td>
			<td style="width:200px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:373px;">1.3 M of lithium hexafluorophosphate (LiPF6) dissolved in EC/DEC with 10 wt% of FEC</td>
			<td style="width:184px;">PANAX ETEC</td>
			<td style="width:200px;"></td>
			<td>In a stainless steel bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Propylene carbonate</td>
			<td style="width:184px;">Sigma Aldrich</td>
			<td style="width:200px;">CAS 108-32-7</td>
			<td>In a glass bottle</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Super P Carbon Black</td>
			<td style="width:184px;">Alfa-Aesar</td>
			<td style="width:200px;">CAS 1333-86-4</td>
			<td>In a glass bottle</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:373px;">Cell components (bottom cell, top cell, separator, gasket, spring, spacer)</td>
			<td style="width:184px;">Wellcos Corporation</td>
			<td style="width:200px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Cell punch</td>
			<td style="width:184px;">Wellcos Corporation</td>
			<td style="width:200px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:373px;">Glove Box</td>
			<td style="width:184px;">Moisture Oxygen Technology (MOTEK)</td>
			<td style="width:200px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Box Furnace</td>
			<td style="width:184px;">Naytech</td>
			<td style="width:200px;">Vulcan 3-550</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Electrospinning device</td>
			<td style="width:184px;">NanoNC</td>
			<td style="width:200px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Hydrofluoric acid</td>
			<td style="width:184px;">Junsei</td>
			<td style="width:200px;">84045-0350</td>
			<td>85%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Cu foil</td>
			<td style="width:184px;">Alfaaesar</td>
			<td style="width:200px;">38381</td>
			<td>Copper Thinfoil, 0.0125mm thick, 99.9%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Holy carbon Au grid</td>
			<td style="width:184px;">SPI</td>
			<td>Quantifoil R2/2 Micromachined Holey Carbon Grids, 300 Mesh Gold</td>
			<td>Quantifoil R2/2 Micromachined Holey Carbon Grids, 300 Mesh Gold</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Isoprophyl alchol</td>
			<td style="width:184px;">Sigmaaldrich</td>
			<td style="width:200px;">W292907</td>
			<td>99.70%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Ammonium persulfate</td>
			<td style="width:184px;">Sigmaaldrich</td>
			<td style="width:200px;">248614</td>
			<td>98%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Transmission electron microscope (TEM)</td>
			<td style="width:184px;">JEOL</td>
			<td style="width:200px;">JEOL JEM 3010</td>
			<td>300 kV</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Chemical vapor depistion (CVD)</td>
			<td style="width:184px;">Scientech</td>
			<td style="width:200px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Charge coupled device (CCD)</td>
			<td style="width:184px;">Gatan</td>
			<td style="width:200px;">Orius SC200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Plasma Cleaner</td>
			<td style="width:184px;">Femtoscience</td>
			<td style="width:200px;">VITA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Electrospinning program</td>
			<td style="width:184px;">NanoNC</td>
			<td style="width:200px;">NanoNC eS- robot</td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation of graphene liquid cells for the observation of lithium-ion battery material

In this work, we introduce the preparation of graphene liquid cells (GLCs), encapsulating both electrode materials and organic liquid electrolytes between two graphene sheets, and the facile synthesis of one-dimensional nanostructures using electrospinning. The GLC enables in situ transmission electron microscopy (TEM) for the lithiation dynamics of electrode materials. The in situ GLC-TEM using an electron beam for both imaging and lithiation can utilize not only realistic battery electrolytes, but also the high-resolution imaging of various morphological, phase, and interfacial transitions.

SnO2 nanotubes were fabricated by electrospinning and subsequent calcination, during which the nanotubular and porous structures could be seen clearly, according to the SEM image (Figure 3a). Such a nanotubular structure comes from the decomposition of PVP, while the Sn precursor in the core is moved outward due to the Kirkendall effect17,18. Additionally, Ostwald ripening occurs in addition to the Kirkendall effect, resulting in the growth of SnO2 nanogains19. The TEM image (Figure 3b) shows that such porous sites are more visually clear, indicated by a number of white spots within the SnO2 nanotubes. The crystal structures of SnO2 are polycrystalline cassiterite structures (Figure 3c), in accordance with previously published literature17.
In terms of electrochemical characteristics of the SnO2 nanotubes, various aspects of the SnO2 nanotubes were examined in detail. To start with, the charge and discharge profile of the SnO2 nanotubes in the formation cycle is shown (Figure 4a), which exhibits stable voltage profiles with an initial coulombic efficiency of 67.8%. The voltage plateau, which exists at 0.9 V, can be attributed to the two-phase reaction (the conversion reaction of SnO2 to Sn), similar to descriptions in previous works9,20. The irreversible formation of Li2O during the conversion reaction of SnO2, along with the unstable formation of the solid electrolyte interphase (SEI) layer, resulted in a poorly reversible reaction with Li in the formation cycle. The SnO2 nanotubes exhibit stable cycling at 500 mA g-1, with coulombic efficiencies above 98% (Figure 4b). The rate capabilities of SnO2 nanotubes (Figure 4c) are also presented, where the SnO2 nanotubes retain considerable capacity (&#62; 700 mAh g-1) even at a high current density of 1,000 mA g-1. Nevertheless, initial irreversible capacity loss needs to be examined more in detail using in situ TEM methods.
Overall characterizations of graphene are shown in Figure 5. Figure 5a shows the Raman spectrum of graphene synthesized on Cu foil. The ratio between Ig and I2D was 2.81, which matches well with the ratio of monolayer graphene on polycrystalline Cu substrate, indicating that monolayer graphene was synthesized. The SEM image of transferred graphene on an Au TEM grid is shown in Figure 5b, demonstrating that the coverage of graphene was good after its transfer to the Au TEM grid. The TEM image and the corresponding selected area electron diffraction (SAED) pattern of the transferred graphene are shown in Figure 5c,d. The hexagonal diffraction spots indicate the monolayer graphene well.
Time-series TEM images of GLCs are shown in Figure 6, which are captured from Movie S1. When GLCs are fabricated well, they have multiple liquid pockets whose sizes range from tens of nanometers to hundreds of nanometers, depending on the solution and nanoparticles7,14. In this experiment, using EC/DEC/FEC solution and SnO2 nanotubes, the size of the liquid pocket was 300 - 400 nm. The accelerating voltage was 300 kV and the electron beam dosage 743.9 e-/&#197;2&#183;s, which is enough for lithiation to proceed but not for severe beam damage. Through constant electron beam irradiation, dissolved electrons and radicals trigger a secondary reaction with the salt and solvent. Here, the decomposition of electrolyte and the formation of an SEI layer were observed at the initial stage, in agreement with some of the previously reported on reuslts6,7,8,9,21.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/58676/58676fig1.jpg" /> 
Figure 1: Digital camera images of the electrospinning setup and prepared SnO2 nanotubes and electrode. (a) Electrospinning, (b) SnO2 nanotubes, and (c) the slurry-cast electrode. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58676/58676fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/58676/58676fig2.jpg" /> 
Figure 2: Digital camera images showing the graphene-transferred grid and fabrication of the graphene liquid cells. (a) The synthesized monolayer graphene on Cu foil, (b) an Au TEM grid on Cu foil, (c) the etching process of Cu foils in 0.1 M ammonium persulfate, and (d) stacked Au grids inside a glove box. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58676/58676fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/58676/58676fig3.jpg" /> 
Figure 3: Characterization of SnO2 nanotubes before their encapsulation inside the graphene sheet. These panels show (a) an SEM image, (b) a TEM image, and (c) the SAED pattern of the SnO2 nanotubes. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58676/58676fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/58676/58676fig4.jpg" /> 
Figure 4: Electrochemical battery cell testing of the SnO2 nanotubes. These panels show (a) the charge and discharge profile, (b) the cycle retention characteristics, and (c) the rate capabilities of the SnO2 nanotubes. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58676/58676fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/58676/58676fig5.jpg" /> 
Figure 5: Characterization of synthesized graphene. These panels show (a) the Raman spectrum, (b) the SEM image, (c) the TEM image, and (d) the SAED pattern of the monolayer graphene. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58676/58676fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/58676/58676fig6.jpg" /> 
Figure 6: Real-time TEM images of the lithiation process of GLCs. Decomposed electrolyte and the formation of an SEI layer on the surface of an SnO2 nanotube are observed for 0 - 45 s. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58676/58676fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Movie 1" src="/files/ftp_upload/58676/58676movie1.jpg" /> 
Movie S1. Lithiation of GLCs. The surface of an SnO2 nanotube is visualized inside liquid electrolyte. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/58676/Movie_S1_(x4_faster).avi" target="_blank">Please click here to view this video. (Right-click to download.)</a>

Watch this Scientific Journal Video about Preparation of Graphene Liquid Cells for the Observation of Lithium-ion Battery Material at JoVE.com

Preparation of Graphene Liquid Cells for the Observation of Lithium-ion Battery Material

Here, we present a protocol for the fabrication and preparation of a graphene liquid cell for in situ transmission electron microscopy observation, along with a synthesis of electrode materials and electrochemical battery cell tests.

In this work, we introduce the preparation of graphene liquid cells (GLCs), encapsulating both electrode materials and organic liquid electrolytes between ...

preparation-graphene-liquid-cells-for-observation-lithium-ion-battery

Nanyang Technological University

Research

JoVE Journal

Engineering

8.9K Views.  Korea Advanced Institute of Science and Technology. Here, we present a protocol for the fabrication and preparation of a graphene liquid cell for in situ transmission electron microscopy observation, along with a synthesis of electrode materials and electrochemical battery cell tests.

Video: Preparation of Graphene Liquid Cells for the Observation of Lithium-ion Battery Material

Construction and Testing of Coin Cells of Lithium Ion Batteries

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime. Lithium ion batteries have also been considered to be used in electric and hybrid vehicles1 or even electrical grid stabilization systems2. All these applications simulate a dramatic increase in the research and development of battery materials3-7, including new materials3,8, doping9, nanostructuring10-13, coatings or surface modifications14-17 and novel binders18. Consequently, an increasing number of physicists, chemists and materials scientists have recently ventured into this area. Coin cells are widely used in research laboratories to test new battery materials; even for the research and development that target large-scale and high-power applications, small coin cells are often used to test the capacities and rate capabilities of new materials in the initial stage. 
 In 2010, we started a National Science Foundation (NSF) sponsored research project to investigate the surface adsorption and disordering in battery materials (grant no. DMR-1006515). In the initial stage of this project, we have struggled to learn the techniques of assembling and testing coin cells, which cannot be achieved without numerous help of other researchers in other universities (through frequent calls, email exchanges and two site visits). Thus, we feel that it is beneficial to document, by both text and video, a protocol of assembling and testing a coin cell, which will help other new researchers in this field. This effort represents the "Broader Impact" activities of our NSF project, and it will also help to educate and inspire students.
In this video article, we document a protocol to assemble a CR2032 coin cell with a LiCoO2 working electrode, a Li counter electrode, and (the mostly commonly used) polyvinylidene fluoride (PVDF) binder. To ensure new learners to readily repeat the protocol, we keep the protocol as specific and explicit as we can. However, it is important to note that in specific research and development work, many parameters adopted here can be varied. First, one can make coin cells of different sizes and test the working electrode against a counter electrode other than Li. Second, the amounts of C black and binder added into the working electrodes are often varied to suit the particular purpose of research; for example, large amounts of C black or even inert powder were added to the working electrode to test the "intrinsic" performance of cathode materials14. Third, better binders (other than PVDF) have also developed and used18. Finally, other types of electrolytes (instead of LiPF6) can also be used; in fact, certain high-voltage electrode materials will require the uses of special electrolytes7.

A protocol to construct and test coin cells of lithium ion batteries is described. The specific procedures of making a working electrode, preparing a counter electrode, assembling a cell inside a glovebox and testing the cell are presented.

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime.  Lithium ion ...

Probing and Mapping Electrode Surfaces in Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen 1-7. The performance of SOFCs and the rates of many chemical and energy transformation processes in energy storage and conversion devices in general are limited primarily by charge and mass transfer along electrode surfaces and across interfaces. Unfortunately, the mechanistic understanding of these processes is still lacking, due largely to the difficulty of characterizing these processes under in situ conditions. This knowledge gap is a chief obstacle to SOFC commercialization. The development of tools for probing and mapping surface chemistries relevant to electrode reactions is vital to unraveling the mechanisms of surface processes and to achieving rational design of new electrode materials for more efficient energy storage and conversion2. Among the relatively few in situ surface analysis methods, Raman spectroscopy can be performed even with high temperatures and harsh atmospheres, making it ideal for characterizing chemical processes relevant to SOFC anode performance and degradation8-12. It can also be used alongside electrochemical measurements, potentially allowing direct correlation of electrochemistry to surface chemistry in an operating cell. Proper in situ Raman mapping measurements would be useful for pin-pointing important anode reaction mechanisms because of its sensitivity to the relevant species, including anode performance degradation through carbon deposition8, 10, 13, 14 ("coking") and sulfur poisoning11, 15 and the manner in which surface modifications stave off this degradation16. The current work demonstrates significant progress towards this capability. In addition, the family of scanning probe microscopy (SPM) techniques provides a special approach to interrogate the electrode surface with nanoscale resolution. Besides the surface topography that is routinely collected by AFM and STM, other properties such as local electronic states, ion diffusion coefficient and surface potential can also be investigated17-22. In this work, electrochemical measurements, Raman spectroscopy, and SPM were used in conjunction with a novel test electrode platform that consists of a Ni mesh electrode embedded in an yttria-stabilized zirconia (YSZ) electrolyte. Cell performance testing and impedance spectroscopy under fuel containing H2S was characterized, and Raman mapping was used to further elucidate the nature of sulfur poisoning. In situ Raman monitoring was used to investigate coking behavior. Finally, atomic force microscopy (AFM) and electrostatic force microscopy (EFM) were used to further visualize carbon deposition on the nanoscale. From this research, we desire to produce a more complete picture of the SOFC anode.

We present a unique platform for characterizing electrode surfaces in solid oxide fuel cells (SOFCs) that allows simultaneous performance of multiple characterization techniques (e.g. in situ Raman spectroscopy and scanning probe microscopy alongside electrochemical measurements). Complementary information from these analyses may help to advance toward a more profound understanding of electrode reaction and degradation mechanisms, providing insights into rational design of better materials for SOFCs.

Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution to utilization of a wide variety of fuels beyond hydrogen ...

Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. During insertion or removal of alkali metal ions, the redox states of transition metals in the compounds change and structural transformations such as phase transitions and/or lattice parameter increases or decreases occur. These behaviors in turn determine important characteristics of the batteries such as the potential profiles, rate capabilities, and cycle lives. The extremely bright and tunable x-rays produced by synchrotron radiation allow rapid acquisition of high-resolution data that provide information about these processes. Transformations in the bulk materials, such as phase transitions, can be directly observed using X-ray diffraction (XRD), while X-ray absorption spectroscopy (XAS) gives information about the local electronic and geometric structures (e.g.&#160;changes in redox states and bond lengths). In situ experiments carried out on operating cells are particularly useful because they allow direct correlation between the electrochemical and structural properties of the materials. These experiments are time-consuming and can be challenging to design due to the reactivity and air-sensitivity of the alkali metal anodes used in the half-cell configurations, and/or the possibility of signal interference from other cell components and hardware. For these reasons, it is appropriate to carry out ex situ experiments (e.g.&#160;on electrodes harvested from partially charged or cycled cells) in some cases. Here, we present detailed protocols for the preparation of both ex situ and in situ samples for experiments involving synchrotron radiation and demonstrate how these experiments are done.

We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li-ion and Na-ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. ...

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries

Li-ion batteries are widely used in portable electronic devices and are considered as promising candidates for higher-energy applications such as electric vehicles.1,2 However, many challenges, such as energy density and battery lifetimes, need to be overcome before this particular battery technology can be widely implemented in such applications.3 This research is challenging, and we outline a method to address these challenges using in situ NPD to probe the crystal structure of electrodes undergoing electrochemical cycling (charge/discharge) in a battery. NPD data help determine the underlying structural mechanism responsible for a range of electrode properties, and this information can direct the development of better electrodes and batteries.
We briefly review six types of battery designs custom-made for NPD experiments and detail the method to construct the &#8216;roll-over&#8217; cell that we have successfully used on the high-intensity NPD instrument, WOMBAT, at the Australian Nuclear Science and Technology Organisation (ANSTO). The design considerations and materials used for cell construction are discussed in conjunction with aspects of the actual in situ NPD experiment and initial directions are presented on how to analyze such complex in situ data.

In Situ Neutron Powder Diffraction Using Custom-made Lithium-ion Batteries

We describe the design and construction of an electrochemical cell for the examination of electrode materials using in situ neutron powder diffraction (NPD). We briefly comment on alternate in situ NPD cell designs and discuss methods for the analysis of the corresponding in situ NPD data produced using this cell.

Li-ion batteries are widely used in portable electronic devices and are considered as promising candidates for higher-energy applications such as electric ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 &#176;C. Measured free dielectric constants <img alt="Equation 1" src="/files/ftp_upload/53461/image001.jpg" /> and&#160;<img alt="Equation 2" src="/files/ftp_upload/53461/image002.jpg" /> were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS.

This protocol describes the procedure of measuring the temperature dependence of the full set material constants of piezoelectric materials using resonant ultrasound spectroscopy (RUS).

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Non-aqueous Electrode Processing and Construction of Lithium-ion Coin Cells

Research into new and improved materials to be utilized in lithium-ion batteries (LIB) necessitates an experimental counterpart to any computational analysis. Testing of lithium-ion batteries in an academic setting has taken on several forms, but at the most basic level lies the coin cell construction. In traditional LIB electrode preparation, a multi-phase slurry composed of active material, binder, and conductive additive is cast out onto a substrate. An electrode disc can then be punched from the dried sheet and used in the construction of a coin cell for electrochemical evaluation. Utilization of the potential of the active material in a battery is critically dependent on the microstructure of the electrode, as an appropriate distribution of the primary components are crucial to ensuring optimal electrical conductivity, porosity, and tortuosity, such that electrochemical and transport interaction is optimized. Processing steps ranging from the combination of dry powder, wet mixing, and drying can all critically affect multi-phase interactions that influence the microstructure formation. Electrochemical probing necessitates the construction of electrodes and coin cells with the utmost care and precision. This paper aims at providing a step-by-step guide of non-aqueous electrode processing and coin cell construction for lithium-ion batteries within an academic setting and with emphasis on deciphering the influence of drying and calendaring.

Non-aqueous electrode processing is central to the construction of coin cells and the evaluation of new electrode chemistries for lithium-ion batteries. A step-by-step guide to the basic practices needed as an electrochemical engineer working with batteries in an academic experimental setting is furnished.

Research into new and improved materials to be utilized in lithium-ion batteries (LIB) necessitates an experimental counterpart to any computational ...

High-speed Continuous-wave Stimulated Brillouin Scattering Spectrometer for Material Analysis

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as aqueous solutions and biomaterials, with fast acquisition times. Here, we discuss the assembly and operation of a Brillouin spectrometer that uses stimulated Brillouin scattering (SBS) to measure stimulated Brillouin gain (SBG) spectra of water and lipid emulsion-based tissue-like samples in transmission mode with &lt;10 MHz spectral-resolution and &lt;35 MHz Brillouin-shift measurement precision at &lt;100 ms. The spectrometer consists of two nearly counter-propagating continuous-wave (CW) narrow-linewidth lasers at 780 nm whose frequency detuning is scanned through the material Brillouin shift. By using an ultra-narrowband hot rubidium-85 vapor notch filter and a phase-sensitive detector, the signal-to-noise-ratio of the SBG signal is significantly enhanced compared to that obtained with existing CW-SBS spectrometers. This improvement enables measurement of SBG spectra with up to 100-fold faster acquisition times, thereby facilitating high spectral-resolution and high-precision Brillouin analysis of soft materials at high speed.

We describe the construction of a rapid continuous-wave-stimulated-Brillouin-scattering (CW-SBS) spectrometer. The spectrometer employs single-frequency diode-lasers and an atomic vapor notch-filter to acquire transmission spectra of turbid/non-turbid samples with high spectral-resolution at speeds up to 100-fold faster than those of existing CW-SBS spectrometers. This improvement enables high-speed Brillouin material analysis.

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as ...

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

Solid-state electrolytes are a promising replacement for current organic liquid electrolytes, enabling higher energy densities and improved safety of lithium-ion (Li-ion) batteries. However, a number of setbacks prevent their integration into commercial devices. The main limiting factor is due to nanoscale phenomena occurring at the electrode/electrolyte interfaces, ultimately leading to degradation of battery operation. These key problems are highly challenging to observe and characterize as these batteries contain multiple buried interfaces. One approach for direct observation of interfacial phenomena in thin film batteries is through the fabrication of electrochemically active nanobatteries by a focused ion beam (FIB). As such, a reliable technique to fabricate nanobatteries was developed and demonstrated in recent work. Herein, a detailed protocol with a step-by-step process is presented to enable the reproduction of this nanobattery fabrication process. In particular, this technique was applied to a thin film battery consisting of LiCoO2/LiPON/a-Si, and has further been previously demonstrated by in situ cycling within a transmission electron microscope.

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

A protocol for the fabrication of electrochemically active LiPON-based solid-state lithium-ion nanobatteries using a focused ion beam is presented.

Solid-state electrolytes are a promising replacement for current organic liquid electrolytes, enabling higher energy densities and improved safety of ...

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous light irradiation. The photo-excitation of dopants that can quickly dissipate light into heat, coupled with anisotropic thermal expansion and self-shadowing of the film, gives rise to the self-sustained deformation. The oscillations observed are influenced by the dimensions and the modulus of the film, and by the directionality and intensity of the light. The system developed offers applications in energy conversion and harvesting for soft-robotics and automated systems.
The general method described here consists of creating free-standing liquid crystalline films and characterizing the mechanical and thermal effects observed. The molecular alignment is achieved using alignment layers (rubbed polyimide), commonly used in the display manufacturing industry. To obtain actuators with large deformation, the mesogens are aligned and polymerized in a splay/bend configuration, i.e., with the director of the liquid crystals (LCs) going gradually from planar to homeotropic through the film thickness. Upon irradiation, the mechanical and thermal oscillations obtained are monitored with a high-speed camera. The results are further quantified by image analysis using an image processing program.

The goal of the protocol is to create liquid crystalline polymer films that can mechanically oscillate under continuous light irradiation. We describe in great detail the conception of free-standing films, from the liquid crystal alignment method to the photo-actuation. The experimental protocol applied to prepare this material is broadly applicable.

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous ...

Three-electrode Coin Cell Preparation and Electrodeposition Analytics for Lithium-ion Batteries

As lithium-ion batteries find use in high energy and power applications, such as in electric and hybrid-electric vehicles, monitoring the degradation and subsequent safety issues becomes increasingly important. In a Li-ion cell setup, the voltage measurement across the positive and negative terminals inherently includes the effect of the cathode and anode which are coupled and sum to the total cell performance. Accordingly, the ability to monitor the degradation aspects associated with a specific electrode is extremely difficult because the electrodes are fundamentally coupled. A three-electrode setup can overcome this problem. By introducing a third (reference) electrode, the influence of each electrode can be decoupled, and the electrochemical properties can be measured independently. The reference electrode (RE) must have a stable potential that can then be calibrated against a known reference, for example, lithium metal. The three-electrode cell can be used to run electrochemical tests such as cycling, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). Three-electrode cell EIS measurements can elucidate the contribution of individual electrode impedance to the full cell. In addition, monitoring the anode potential allows the detection of electrodeposition due to lithium plating, which can cause safety concerns. This is especially important for the fast charging of Li-ion batteries in electric vehicles. In order to monitor and characterize the safety and degradation aspects of an electrochemical cell, a three-electrode setup can prove invaluable. This paper aims to provide a guide to constructing a three-electrode coin cell setup using the 2032-coin cell architecture, which is easy to produce, reliable, and cost-effective.

Three-electrode cells are useful in studying the electrochemistry of lithium-ion batteries. Such an electrochemical setup allows the phenomena associated with the cathode and anode to be decoupled and examined independently. Here, we present a guide for construction and use of a three-electrode coin cell with emphasis on lithium plating analytics.

As lithium-ion batteries find use in high energy and power applications, such as in electric and hybrid-electric vehicles, monitoring the degradation and ...