Name: synthesis of ionic liquid based electrolytes, assembly of li-ion batteries, and measurements of performance at high temperature
Uploaded: 2016-12-20T13:00:00
Description: Watch this Scientific Journal Video about Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature at JoVE.com

This article was supported in part by BU and by the Advanced Energy Consortium:

1.Synthesis of Mono- and Di-phosphonium Ionic Liquids Paired with Chloride (Cl) and Bis(trifluoromethane)sulfonimide (TFSI) Anions
NOTE: The procedure for the mono-phosphonium ionic liquid possessing three hexyl and one decyl alkyl chain surrounding the phosphonium cation is described, and this ionic liquid is abbreviated as mono-HexC10Cl. The same procedure is repeated using 1,10-dichlorodecane to obtain the di-phosphonium ionic liquid in high yield, and this ionic liquid is abbreviated as di-H...

<ol>
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Our approach to develop non-flammable and high temperature functional Li-ion batteries involves the synthesis of new ionic liquid electrolytes and their subsequent evaluation in prototypical coin cells. Specifically, mono-HexC10TFSI and di-HexC10TFSI based electrolytes were tested in a coin cell possessing a Li metal anode and LiCoO2 cathode. The critical steps within this approach are to: 1) identify the lead electrolyte according to a set of design specifications; 2) maintain dryness and ensure water does no...

Li-ion batteries are devices that transform energy between electrical energy and chemical energy and provide a convenient means to store and to deliver energy on demand and on-the-go. Today, Li-ion batteries dominate the portable electronics market because of their high energy density and re-chargeability, and are of interest for large-scale and specialty applications, such as down-hole drilling and automotive.1-5 Batteries are composed of four primary components: cathode, anode, separator, and electrolyte. While the chemistry of the two electrodes dictates the theoretical energy density of the battery, the safety and working temperature are mainly limited by the electrolyte material.6-9 Carbonate based organic solvent electrolytes (e.g., dimethyl carbonate (DMC) and ethylene carbonate (EC)) are widely used in Li-ion batteries due to their low viscosity, high conductivity, and high lithium salt solubility. Moreover, certain combinations of the carbonate solvents (DMC/EC) also form a stable solid electrolyte interface (SEI), thereby preventing degradation reactions between the electrolyte and the electrode, and extending battery life. However, carbonate solvents suffer from low boiling points and flash points, limiting the operation temperature of Li-ion batteries to below 55 &#176;C, with potentially severe safety issues when there is a short-circuit.10,11
Ionic liquids are a class of salts that have melting temperatures below 100 &#176;C.12 In contrast to typical inorganic salts, ionic liquids possess a wide liquid range and can be liquid at room temperature. Ionic liquids are composed of one or multiple organic cationic centers, such as imidazolium, phosphonium, pyridinium, or ammonium and paired with an inorganic or organic anion, such as methansulfonate, hexafluorophosphate, or halide.13,14 The wide variety of possible cation and anion combinations allows for a large number of compositions with tunable properties. In addition, the strong ionic interactions within ionic liquids result in negligible vapor pressure, non-flammability, and high thermal and electrochemical stability.15,16
Replacing conventional electrolytes with ionic liquids is one solution that addresses the inherent safety issues in current Li-ion batteries, and could enable high temperature applications.17-27 To illustrate the general synthetic and material processing methods utilized to construct lithium ion batteries containing ionic liquids for high temperature applications, we describe the synthesis, thermal properties, and electrochemical characterization of mono- and di-phosphonium ionic liquids paired with either the chloride (Cl) or bis(trifluoromethane)sulfonimide (TFSI) anion. Different concentrations of lithium bis(trifluoromethane)sulfonimide (LiTFSI) are subsequently added to the phosphonium ionic liquids to give electrolytes. Based on the performance of the phosphonium TFSI electrolytes with added LiTFSI compared to the chloride analogs, a coin cell is constructed with either the mono- or di-phosphonium TFSI electrolytes along with a Li metal anode and LiCoO2 cathode. Finally, battery performance is evaluated at 100 &#176;C for the two different coin cell batteries. The detailed procedures, the challenges in execution, and the insights gained from performing these experiments are described below.

<table border="0" cellpadding="0" cellspacing="0" width="653">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Silicone oil</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">85409</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Potassium hydroxide</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">221473</td>
			<td>Corrosive</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Rotary evaporator</td>
			<td style="width:108px;">Buchi</td>
			<td style="width:119px;">R-124</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">High-vacuum pump</td>
			<td style="width:108px;">Welch</td>
			<td align="right" style="width:119px;">8907</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Nitrogen, ultra high purity</td>
			<td style="width:108px;">Airgas</td>
			<td style="width:119px;">NI UHP300</td>
			<td>Compressed gas</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Tetrahydrofuran, stabilized with BHT</td>
			<td style="width:108px;">Pharmaco-Aaper</td>
			<td align="right" style="width:119px;">346000</td>
			<td>Flammable. Dried through column of XXX</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Dichloromethane</td>
			<td style="width:108px;">Pharmaco-Aaper</td>
			<td align="right" style="width:119px;">313000</td>
			<td>Flammable, toxic.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Separatory funnel (1 L)</td>
			<td style="width:108px;">Fisher Scientific</td>
			<td style="width:119px;">13-678-606</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Sodium sulfate</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">239313</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Ethanol, absolute</td>
			<td style="width:108px;">Pharmaco-Aaper</td>
			<td style="width:119px;">111USP200</td>
			<td>Flammable, toxic.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Buchner funnel</td>
			<td style="width:108px;">Fisher Scientific</td>
			<td style="width:119px;">FB-966-F</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Methanol</td>
			<td style="width:108px;">Pharmaco-Aaper</td>
			<td style="width:119px;">339000ACS</td>
			<td>Flammable, toxic.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Triethylamine (anhydrous)</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">471283</td>
			<td>Toxic, flammable, harmful to environment</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Glass syringe</td>
			<td style="width:108px;">Hamilton Company</td>
			<td style="width:119px;">1700-series</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:259px;">Deuterated chloroform</td>
			<td style="width:108px;">Cambridge Isotopes Laboratories, Inc.</td>
			<td style="width:119px;">DLM-29-10</td>
			<td>Toxic</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Nuclear magnetic resonance instrument</td>
			<td style="width:108px;">Varian</td>
			<td style="width:119px;">V400</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Hydrogen</td>
			<td style="width:108px;">Airgas</td>
			<td style="width:119px;">HY HP300</td>
			<td>Highly flammable.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Hexanes</td>
			<td style="width:108px;">Pharmaco-Aaper</td>
			<td style="width:119px;">359000ACS</td>
			<td>Toxic, flammable.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Differential scanning calorimeter</td>
			<td style="width:108px;">TA Instruments</td>
			<td style="width:119px;">Q100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">N,N-dimethylformamide</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td align="right" style="width:119px;">227056</td>
			<td>Toxic, flammable.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Trihexylphosphone</td>
			<td style="width:108px;">TCI America</td>
			<td style="width:119px;"></td>
			<td>Toxic, flammable.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">1-Chlorodecane</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td>Toxic, flammable.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Bis(trifluoromethane)sulfonimide lithium salt</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td>Hydrophilic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">1, 10-dichlorodecane</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;"></td>
			<td>Toxic, flammable.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Thermal Gravemetric Analysis (TGA)</td>
			<td style="width:108px;">TA Q50</td>
			<td style="width:119px;">TA instruments</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Differential scanning calorimeter (DSC)</td>
			<td style="width:108px;">TA Q100</td>
			<td style="width:119px;">TA instruments</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Controlled Strain Rheometer</td>
			<td style="width:108px;">AR 1000&#160;</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Conductivity Meter&#160;</td>
			<td style="width:108px;">Consort</td>
			<td style="width:119px;">K912</td>
			<td>4-electrode cell</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;">Potentiostate/Galvanostat</td>
			<td style="width:108px;">Princeton Applied Research&#160;</td>
			<td style="width:119px;">VersaStat MC4&#160;</td>
			<td style="width:167px;">Electrochemical testing</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Separators&#160;</td>
			<td style="width:108px;">Celgard&#160;</td>
			<td style="width:119px;">C480&#160;</td>
			<td style="width:167px;">polypropylene/polyethylene</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">CR2032 coin cells</td>
			<td style="width:108px;">MTI Corp.</td>
			<td style="width:119px;">EQ-CR2032-CASE</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">LiCoO2 electrode&#160;</td>
			<td style="width:108px;">MTI Corp.</td>
			<td style="width:119px;">EQ-CR2032</td>
			<td style="width:167px;">Cathode material</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">lithium metal&#160;</td>
			<td style="width:108px;">Alfa Aesar</td>
			<td align="right" style="width:119px;">10769</td>
			<td style="width:167px;">Anode Material</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Stainless Steel Spacer</td>
			<td style="width:108px;">MTI Corp.</td>
			<td style="width:119px;">EQ-CR20-Spacer304-02</td>
			<td style="width:167px;">15.5 mm Dia x 0.2 mm</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Wave Spring</td>
			<td style="width:108px;">MTI Corp.</td>
			<td style="width:119px;">EQ-CR20WS-Spring304</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Electric Coin Cell Crimping Machine</td>
			<td style="width:108px;">MTI Corp.</td>
			<td style="width:119px;">MSK-160D</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">Glove box</td>
			<td style="width:108px;">Mbraun</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Water free, oxygen free operation</td>
		</tr>
	</tbody>
</table>

synthesis of ionic liquid based electrolytes, assembly of li-ion batteries, and measurements of performance at high temperature

The chemical instability of the traditional electrolyte remains a safety issue in widely used energy storage devices such as Li-ion batteries. Li-ion batteries for use in devices operating at elevated temperatures require thermally stable and non-flammable electrolytes. Ionic liquids (ILs), which are non-flammable, non-volatile, thermally stable molten salts, are an ideal replacement for flammable and low boiling point organic solvent electrolytes currently used today. We herein describe the procedures to: 1) synthesize mono- and di-phosphonium ionic liquids paired with chloride or bis(trifluoromethane)sulfonimide (TFSI) anions; 2) measure the thermal properties and stability of these ionic liquids by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA); 3) measure the electrochemical properties of the ionic liquids by cyclic voltammetry (CV); 4) prepare electrolytes containing lithium bis(trifluoromethane)sulfonamide; 5) measure the conductivity of the electrolytes as a function of temperature; 6) assemble a coin cell battery with two of the electrolytes along with a Li metal anode and LiCoO2 cathode; and 7) evaluate battery performance at 100 &#176;C. We additionally describe the challenges in execution as well as the insights gained from performing these experiments.

The ionic liquids, mono-HexC10Cl and di-HexC10Cl, were prepared via a nucleophilic reaction, and a subsequent halide exchange reaction gave the mono-HexC10TFSI and di-HexC10TFSI ionic liquids, respectively (Figure 1A).14 All four ionic liquids were colorless and slightly viscous liquids (Figure 1B). A representative 1H NMR of the mono-HexC10TFSI ionic liquid is shown in Figure 1C, and along with mass spectrometry and...

Watch this Scientific Journal Video about Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature at JoVE.com

Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature

Here, we describe protocols to prepare phosphonium-based ionic liquid and lithium bis(trifluoromethane)sulfonimide salt electrolytes, and assemble a non-flammable and high temperature functioning lithium-ion coin cell battery.

The chemical instability of the traditional electrolyte remains a safety issue in widely used energy storage devices such as Li-ion batteries. Li-ion ...

The overall goal of this procedure is to assemble a high-temperature functioning lithium ion battery that utilizes a non-flammable, thermally stable phosphonium-based ion liquid electrolyte containing lithium bis trifluoromethane sulfonamide. This method addresses key challenges in a high temperature energy storage field, specifically the safety issues with the use of conventional electrolytes in lithium ion batteries. The main advantage of this technique is that it provides an approach to synthesize and characterize thermally stable electrolytes and to construct high temperature functioning lithium ion batteries.Though this method provides insight into rational design bionic liquid electrolytes optimized for lithium ion batteries, it can also be applied to super capacitors and other energy storage devices. Generally, individuals new to this method struggle because the measurements will be taken under inert atmosphere with extremely dry materials. Visual demonstration of this method is critical as introduction of bionic liquids in the batteries is challenging due to their high viscosities.In an argon-filled glove box, use glass pipettes to dispense 8.3 grams of trihexyl phosphene and 5.22 grams of 1-chlorodecane into an oven-dried heavy wall pressure vessel containing a stir bar. Cap the vessel with a PTFE bushing and stir the mixture under argon at 140 degrees Celsius for 24 hours. Remove volatiles under vacuum at 140 degrees to obtain crude mono-hexe-10-chloride.Extract the mono-hexe-10-chloride into DCM three times with ten milliliter portions of a one to one mixture of DCM and brine. Remove volatiles from the DCM phase to isolate the mono-hexe-10-chloride product. Next, dissolve 6.25 grams of lithium TFSI in ten milliliters of deionized water.Then, dissolve 7.75 grams of mono-hexe-10-chloride in ten milliliters of DCM. Add the TFSI solution. Cap the container and stir the mixture at room temperature for 24 hours to obtain crude mono-hexe-10-TFSI.Extract the mono-hexe-10-TFSI into 20 milliliters of DCM three times. Test for the presence of chloride by adding one to two drops of one normal silver nitrate solution to one milliliter of the DCM phase. Repeat the extraction if silver chloride is observed as a white precipitate.Then, dry the mono-hexe-10-TFSI solution with one gram of anhydrous magnesium sulfate. Decant the dried solution and remove the solvent with a rotary evaporator to isolate the product. To synthesize the di-phosphonium analogues follow this procedure using 1, 10-dichlorodecane and appropriately adjust its molar ratios.To perform viscosity measurements, set up a controlled strain rheometer in a nitrogen gas-filled glove bag. Place one milliliter of the ionic liquid onto the Peltier stage of the rheometer ensuring that the aluminium plate is fully covered. Set the gap between the sample and a parallel 20 millimeter diameter aluminium plate to be one to two millimeters in all of the test runs.Pre-shear the sample at a shear rate of 100 Hertz for ten seconds and then perform a 15 minute equilibrium step. Then, determine the linear visco-elastic region or LVR with an oscillatory strain sweep at a fixed frequency of one Hertz with a strain amplitude from 0.1 to ten percent. Select a strain within the LVR and perform an oscillatory frequency sweep from 0.1 to ten Hertz.Determine the complex viscosity at a chosen frequency and strain. Then, at that frequency and strain, perform an oscillatory temperature sweep from ten to 95 degrees Celsius at five degree increments with one minute of equilibrium at each temperature. To measure the sample conductivity, first dry the ionic liquid at 100 degrees Celsius under vacuum for 12 hours.Place about four milliliters of the ionic liquid in a test tube. Insert the conductivity probe and add more sample as needed to cover the probe sensor completely. Heat the sample to the first measurement temperature while stirring.Equilibrate the sample at that temperature for 30 minutes and then take the conductivity reading. Repeat this process for each temperature point. Next, set up a lithium-lithium platinum three electrode cyclic voltammetry assembly in the glove box.Place the ionic liquid in the CV chamber, immerse the electrodes in the liquid and ensure that the chamber is sealed. Equilibrate the sample at the first measurement temperature for 20 minutes and then sweep the potential at a rate of one millivolt per second between negative 0.2 volts and 6.5 volts. First is the lithium ion lithium reference potential.Repeat this measurement for each desired temperature. Prior to beginning the battery fabrication, dry the lithium TFSI for three days in a vacuum oven at 70 degrees Celsius. Dry the ionic liquid to be tested under high vacuum at 100 degrees Celsius for 24 hours while stirring vigorously.Bring both dry liquids and an oven-dried flask and stir bar into a glove box. Place 6.4 millimoles each of the ionic liquid and lithium TFSI in the flask. Stir the mixture overnight to obtain a homogenous mixture with a 1.6 molar electrolyte concentration.Dry the coin cell hardware components and a 12.7 millimeter diameter lithium cobalt oxide electrode at 70 degrees Celsius overnight before transferring them to the glove box. Place one spring and stainless steel disk in the coin cell bottom cap. Place the electrode in the steel disk.Heat the electrolyte mixture to 60 degrees Celsius on a hot plate and soak two polypropylene membrane separators in the mixture while stirring for 15 minutes. Cover the surface of the lithium cobalt oxide cathode with about 0.5 milliliters of the electrolyte mixture and then place both separators in the center of the coin cell. Place a few drops of the electrolyte mixture on top of the separators, ensuring that all crevices in the cell are filled.Heat the electrolyte-covered cathode to 60 degrees Celsius for 15 minutes. Cut out a 12.7 millimeter diameter piece of 0.75 millimeter thick lithium metal and place the metal onto the electrolyte-soaked separators. Cap the coin cell and seal it with a crimper.Remove the cell from the glove box and allow the cell to sit for 12 hours. To test the battery performance at high temperatures, thread cables from an electrochemical testing station to the back wall of an oven. Connect the coin cell to the testing station in the oven and leave the cell in the oven for 30 minutes to equilibrate to the oven temperature.At the testing station, select galvanostatic charge-discharge cycling and set the cycle number to 500. Set the charge and discharge parameters and rest times and then start the charge-discharge cycling to evaluate charge output over time. Four phosphonium based ionic liquids were evaluated for use in lithium ion batteries at high temperatures.Thermogravimetric analysis showed that the decomposition temperatures ranged from 340 to 385 degrees Celsius. The TFSI-based ionic liquids were less viscous making them better suited for completely filling pores and crevices in the battery components. Cyclic voltammetry measurements of mono and di-hexC10TFSI with lithium-TFSI in the presence of the lithium cobalt oxide cathode showed the expected lithium cobalt oxide redox peaks.For both liquids, the current increased significantly with temperature. The mono-hexC10TFSI mixture showed a higher current response to all temperatures. Charge-discharge cycling tests of coin cell batteries containing mono-hexC10TFSI at 100 degrees Celsius showed the battery capacity decay was rapid at low concentrations of lithium TFSI.At concentrations nearer the saturation point, the capacity decay was reduced to about ten percent after 20 cycles. An extended galvanostatic charge-discharge cycling test of a coin cell battery containing 1.6 molar TFSI and mono-hexC10TFSI was performed at 100 degrees Celsius. The battery capacity was initially about 135 milliampere hours per gram.After one month, the capacity had decreased to 70 milliampere hours per gram. While attempting this procedure, it's important to thoroughly dry all components of the battery such as the electrolyte and electrodes prior to cell assembly. Moreover, when assembling the coin cell, care must be taken to coat the cathode and separator with the electrolytes.After watching this video, you should be able to synthesize ionic liquid electrolytes and fabricate lithium ion batteries. Care must be taken when handling the ionic liquids since their high viscosities pose additional handling challenges compared to standard electrolytes.

synthesis-ionic-liquid-based-electrolytes-assembly-li-ion-batteries

Research

JoVE Journal

Engineering

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 ...

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. ...

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of biosensing devices. We report on a protocol of using KrF and ArF lasers irradiating Si (001) samples immersed in a liquid environment with low number of pulses and operating at moderately low pulse fluences to induce Si wettability modification. Wafers immersed for up to 4 hr in a 0.01% H2O2/H2O solution did not show measurable change in their initial contact angle (CA) ~75&#176;. However, the 500-pulse KrF and ArF lasers irradiation of such wafers in a microchamber filled with 0.01% H2O2/H2O solution at 250 and 65 mJ/cm2, respectively, has decreased the CA to near 15&#176;, indicating the formation of a superhydrophilic surface. The formation of OH-terminated Si (001), with no measurable change of the wafer&#8217;s surface morphology, has been confirmed by X-ray photoelectron spectroscopy and atomic force microscopy measurements. The selective area irradiated samples were then immersed in a biotin-conjugated fluorescein-stained nanospheres solution for 2 hr, resulting in a successful immobilization of the nanospheres in the non-irradiated area. This illustrates the potential of&#160;the method for selective area biofunctionalization and fabrication of advanced Si-based biosensing architectures. We also describe a similar protocol of irradiation of wafers immersed in methanol (CH3OH) using ArF laser operating at pulse fluence of 65 mJ/cm2 and in situ formation of a strongly hydrophobic surface of Si (001) with the CA of 103&#176;. The XPS results indicate ArF laser induced formation of Si&#8211;(OCH3)x compounds responsible for the observed hydrophobicity. However, no such compounds were found by XPS on the Si surface irradiated by KrF laser in methanol, demonstrating the inability of the KrF laser to photodissociate methanol and create -OCH3 radicals.

We report on a process of in situ alteration of HF treated Si (001) surface into a hydrophilic or hydrophobic state by irradiating samples in microfluidic chambers filled with&#160;H2O2/H2O solution (0.01%-0.5%) or methanol solutions using pulsed UV laser of a relative low pulse fluence.

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of ...

Research and Development of High-performance Explosives

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. For newly developed formulations, the process begins with small-scale mixes, thermal testing, and impact and friction sensitivity. Only then do subsequent larger scale formulations proceed to detonation testing, which will be covered in this paper. Recent advances in characterization techniques have led to unparalleled precision in the characterization of early-time evolution of detonations. The new technique of Photonic Doppler Velocimetry (PDV) for the measurement of detonation pressure will be shared and compared with traditional fiber-optic detonation velocity and plate-dent calculation of detonation pressure. In particular, the role of aluminum in explosive formulations will be discussed. Recent developments led to the development of explosive formulations that result in reaction of aluminum very early in the detonation product expansion. This enhanced reaction leads to changes in the detonation velocity and pressure due to reaction of the aluminum with oxygen in the expanding gas products.

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. This paper will share typical development tests associated with the measurement of detonation velocity and detonation pressure.

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance ...

Failure Analysis of Batteries Using Synchrotron-based Hard X-ray Microtomography

Imaging morphological changes that occur during the lifetime of rechargeable batteries is necessary to understand how these devices fail. Since the advent of lithium-ion batteries, researchers have known that the lithium metal anode has the highest theoretical energy density of any anode material. However, rechargeable batteries containing a lithium metal anode are not widely used in consumer products because the growth of lithium dendrites from the anode upon charging of the battery causes premature cell failure by short circuit. Lithium dendrites can also form in commercial lithium-ion batteries with graphite anodes if they are improperly charged. We demonstrate that lithium dendrite growth can be studied using synchrotron-based hard X-ray microtomography. This non-destructive imaging technique allows researchers to study the growth of lithium dendrites, in addition to other morphological changes inside batteries, and subsequently develop methods to extend battery life.

Synchrotron-based hard X-ray microtomography is used to image the electrochemical growth of dendrites from a lithium metal electrode through a solid polymer electrolyte membrane.

Imaging morphological changes that occur during the lifetime of rechargeable batteries is necessary to understand how these devices fail. Since the advent ...

A High Performance Impedance-based Platform for Evaporation Rate Detection

This paper describes the method of a novel impedance-based platform for the detection of the evaporation rate. The model compound hyaluronic acid was employed here for demonstration purposes. Multiple evaporation tests on the model compound as a humectant with various concentrations in solutions were conducted for comparison purposes. A conventional weight loss approach is known as the most straightforward, but time-consuming, measurement technique for evaporation rate detection. Yet, a clear disadvantage is that a large volume of sample is required and multiple sample tests cannot be conducted at the same time. For the first time in literature, an electrical impedance sensing chip is successfully applied to a real-time evaporation investigation in a time sharing, continuous and automatic manner. Moreover, as little as 0.5 ml of test samples is required in this impedance-based apparatus, and a large impedance variation is demonstrated among various dilute solutions. The proposed high-sensitivity and fast-response impedance sensing system is found to outperform a conventional weight loss approach in terms of evaporation rate detection.

This paper presents an impedance-based apparatus for evaporation rate detection of solutions. It offers clear advantages over a conventional weight loss approach: a fast response, high-sensitivity detection, a small sample requirement, multiple sample measurements, and easy disassembly for cleaning and reuse purposes.

This paper describes the method of a novel impedance-based platform for the detection of the evaporation rate. The model compound hyaluronic acid was ...

Detecting the Water-soluble Chloride Distribution of Cement Paste in a High-precision Way

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a high-precision chloride profile. Firstly, paste specimens are molded, cured, and exposed to cyclic wet-dry conditions. Then, powder samples at different specimen depths are grinded when the exposure age is reached. Finally, the water-soluble chloride content is detected using a silver nitrate titration method, and chloride profiles are plotted. The key to improving the accuracy of the chloride distribution along the depth is to exclude the error in the powderization, which is the most critical step for testing the distribution of chloride. Based on the above concept, the grinding method in this protocol can be used to grind powder samples automatically layer by layer from the surface inward, and it should be noted that a very thin grinding thickness (less than 0.5 mm) with a minimum error less than 0.04 mm can be obtained. The chloride profile obtained by this method better reflects the chloride distribution in specimens, which helps researchers to capture the distribution features that are often overlooked. Furthermore, this method can be applied to studies in the field of cement-based materials, which require high chloride distribution accuracy.

A protocol for obtaining a water-soluble chloride profile by using a high precision milling method is presented.

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a ...

Determination of Aggregate Surface Morphology at the Interfacial Transition Zone (ITZ)

Here, we present a comprehensive method to illustrate the uneven distribution of the interfacial transition zone (ITZ) around the aggregate and the effect of aggregate surface morphology on the formation of ITZ. First, a model concrete sample is prepared with a spherical ceramic particle in roughly the central part of the cement matrix, acting as a coarse aggregate used in common concrete/mortar. After curing until the designed age, the sample is scanned by X-ray computed tomography to determine the relative location of the ceramic particle inside the cement matrix. Three locations of the ITZ are chosen: above the aggregate, on the side of the aggregate, and below the aggregate. After a series of treatments, the samples are scanned with a SEM-BSE detector. The resultant images were further processed using a digital image processing method (DIP) to obtain quantitative characteristics of the ITZ. The surface morphology is characterized at the pixel level based on the digital image. Thereafter, K-means clustering method is used to illustrate the effect of surface roughness on ITZ formation.

Determination of Aggregate Surface Morphology at the Interfacial Transition Zone ITZ

Hereby, we proposed a protocol to illustrate the effect of aggregate surface morphology on the ITZ microstructure. The SEM-BSE image were quantitatively analyzed to obtain ITZ's porosity gradient via digital image processing and a K-means clustering algorithm was further employed to establish a relationship between porosity gradient and surface roughness.

Here, we present a comprehensive method to illustrate the uneven distribution of the interfacial transition zone (ITZ) around the aggregate and the effect ...

Fabrication and Design of Wood-Based High-Performance Composites

Delignified densified wood is a new promising and sustainable material that possesses the potential to replace synthetic materials, such as glass fiber reinforced composites, due to its excellent mechanical properties. Delignified wood, however, is rather fragile in a wet state, which makes handling and shaping challenging. Here we present two fabrication processes, closed-mold densification and vacuum densification, to produce high-performance cellulose composites based on delignified wood, including an assessment of their advantages and limitations. Further, we suggest strategies for how the composites can be re-used or decomposed at the end-of-life cycle. Closed-mold densification has the advantage that no elaborate lab equipment is needed. Simple screw clamps or a press can be used for densification. We recommend this method for small parts with simple geometries and large radii of curvature. Vacuum densification in an open-mold process is suitable for larger objects and complex geometries, including small radii of curvature. Compared to the closed-mold process, the open-mold vacuum approach only needs the manufacture of a single mold cavity.

Delignified densified wood represents a new promising lightweight, high-performance and bio-based material with great potential to partially substitute natural fiber reinforced- or glass fiber reinforced composites in the future. We here present two versatile fabrication routes and demonstrate the possibility to create complex composite parts.

Delignified densified wood is a new promising and sustainable material that possesses the potential to replace synthetic materials, such as glass fiber ...