We gratefully acknowledge the support from the Ceramics program in Division of Materials Research of the U.S. National Science Foundation, under the grant no. DMR-1006515 (program manager, Dr. Lynnette D. Madsen).

1. Preparation of a Working Electrode
<ol>
 <li>Prepare a mixture of ~6 wt. % polyvinylidene fluoride (PVDF) binder in N-methyl-2-pyrrolidone (NMP).</li>
 <li>Weigh 80 wt. % active material (LiCoO2 in this case) and 10 wt. % C black (acetylene, 99.9+ %) and then mix them in a vortex for 1 min.</li>
 <li>Add NMP-binder mixture such that the binder constitutes 10 wt. % of the total weight of the mixture.</li>
 <li>Transfer the above mixture into a small glass vial and mix in the vortex mixer at maximum rpm for about 30 min. Two zirconia balls of 5 mm diameter can be used as media for better mixing. If needed, add more NMP in order to obtain slurry of required consistency.</li>
 <li>Spread a metal foil of the current collector (typically, aluminum for the cathode and copper for the anode) on to a glass plate. Use acetone and ensure that there are no air bubbles between the foil and the glass plate. Use two layers of masking tape to form a track and define the region to be coated.</li>
 <li>Apply the slurry on to the metal foil using a stainless steel spatula and spread the slurry uniformly on to the track using a razor blade.</li>
 <li>Dry the coating in air or vacuum at ~90-120 &deg;C for about 2-8 hours (which should be adjusted dependent on the material and binder used).</li>
 <li>Place the coated metal foil between two steel plates (and two weighing papers to protect the coating) and press under a load of ~3000 lb using a hydraulic press.</li>
 <li>Punch the dried coated metal foil into discs of 8 mm in diameter (preferably inside a glovebox). Weigh the cathodes and wrap them before transferring into the glove box.</li>
 <li>Punch the uncoated metal foil of the same material into discs of 8 mm in diameter and weigh these discs.</li>
</ol>
2. Preparation of Electrolyte
<ol>
 <li>As the electrolyte is photosensitive, store the electrolyte (1M LiPF6 in EC:DMC:DEC in this case) in a Nalgene bottle wrapped by an aluminum foil.</li>
</ol>
3. Preparation of a Counter Electrode (Lithium foil in this case)
<ol>
 <li>Clean the surface of the lithium foil using a nylon brush/stainless steel scalpel until a shiny silvery surface appears (inside an argon glovebox).</li>
 <li>Punch the lithium foil into discs of &frac12; inch diameter (inside an argon glovebox).</li>
</ol>
4. Coin Cell Assembly
<ol>
 <li>Figure 2 shows a schematic of the coin cell assembly.</li>
 <li>Punch Celgard C480 membranes into discs of 19 mm in diameter and use them as separators.</li>
 <li>Transfer coin cell cases (CR2032), springs and spacers (purchased from MTI Corp.), separators and working electrodes into the glove box (after flushing the exchanger five times with argon).</li>
 <li>Assemble the coin cells in the glove box.</li>
 <li>Add two drops of the electrolyte on to the cell cup and place the working electrode on it. Add another three drops of the electrolyte and place two separators with two drops of electrolyte between them. Add two more drops of the electrolyte before placing the lithium counter electrode on it. Place two stainless steel spacers and a spring on the lithium disc.</li>
 <li>Close the cell using the cell cap and crimp 3-4 times using the compact crimping machine (purchased from MTI Corp.).</li>
 <li>After assembling the cells, handle the finished cells using plastic tweezers (to avoid short-circuiting).</li>
 <li>Clean the excess electrolyte leaking from the sides of the cell using a paper napkin.</li>
 <li>The cell is ready for testing and can be taken out of the glovebox.</li>
</ol>
5. Coin Cell Testing
<ol>
 <li>Keep the coin cell connected to the battery tester in the open circuit voltage (OCV) mode for one hour as soon as it is ready.</li>
 <li>Define voltage window for testing the cell based on the active material used in working electrode.</li>
 <li>Calculate the theoretical capacity for the cell using the calculations shown below.</li>
</ol>
Weight of the electrode disc with the current collector =WEO
Weight of the uncoated current collector disc of the same diameter =WCC
Weight of electrode material, WEM, is given by 
<img alt="Equation 1" src="/files/ftp_upload/4104/4104eq1.jpg" />
Weight of active material in the electrode, WAM, is given by 
<img alt="Equation 2" src="/files/ftp_upload/4104/4104eq2.jpg" />
Theoretical capacity for the electrode disc, CED, is given by 
<img alt="Equation 3" src="/files/ftp_upload/4104/4104eq3.jpg" />
where C is the theoretical specific capacity of the active material.
<ol start="4">
 <li>Test the coin cell to charge-discharge cycles at the required C-rate.</li>
</ol>
6. Representative Results
As an example, a coin cell was constructed using LiCoO2 as the active material for the working electrode. After construction, the cell was tested at C/5 rate. The obtained profile is shown in Figure 3. The voltage window was set to be between 3 and 4.3 V for this coin cell. The capacity was 155 mAh/g for the first charge cycle and 140 mAh/g for the first discharge cycle.
<img alt="Figure 1" src="/files/ftp_upload/4104/4104fig1.jpg" /> 
Figure 1. Flow chart of the coin cell construction procedure. First, a working electrode is prepared from the powder of the active material. Then, a counter electrode is prepared from a clean lithium foil and the separators are punched out. Finally, a cell is assembled inside an argon glovebox.
<img alt="Figure 2" src="/files/ftp_upload/4104/4104fig2.jpg" /> 
Figure 2. Schematic of a coin cell assembly process showing all the components in the order that they are placed inside the coin cell case.
<img alt="Figure 3" src="/files/ftp_upload/4104/4104fig3.jpg" /> 
Figure 3. Representative results obtained from a coin cell constructed using a working electrode made from LiCoO2 and a lithium foil counter electrode. The plot shows the first charge and first discharge curves for the coin cell that was charged and discharged at C/5 rate.
<img alt="Figure 4" src="/files/ftp_upload/4104/4104fig4.jpg" /> 
Figure 4. Comparison of good and bad coatings after they have been dried. A cracked coating typically results from slurry that has excess NMP and a porous coating typically results from slurry that has insufficient NMP.
<img alt="Figure 5" src="/files/ftp_upload/4104/4104fig5.jpg" /> 
Figure 5. Comparison of a well crimped coin cell and a badly crimped coin cell, along with an un-crimped cell. Typically, a badly crimped coin cell splits open after a few hours in ambient due to the swelling of lithium foil after reaction with moisture.

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No conflicts of interest declared.

In our experience, the most critical step in the preparation of the working electrode is making good slurries with consistency. As shown in Figure 4, excess NMP in the slurry can result in a cracked coating, while insufficient NMP can result in a porous coating. In the work presented here, CR2032 coin cell cases that are 20 mm in diameter are used. It should be noted that coin cell cases of different sizes can be used, where the electrode sizes should be varied accordingly. During cell assembly, the appr...

<table border="1">
 <tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 </tr>
 <tr>
 <td>Poly(vinylidene fluoride)</td>
 <td>Sigma-Aldrich</td>
 <td>182702</td>
 </tr>
 <tr>
 <td>1-Methyl-2-pyrrolidinone, 99.5%</td>
 <td>Alfa Aesar</td>
 <td>31903</td>
 </tr>
 <tr>
 <td>LiCoO2</td>
 <td>Alfa Aesar</td>
 <td>42090</td>
 </tr>
 <tr>
 <td>Carbon black, acetylene, 99.9+%</td>
 <td>Alfa Aesar</td>
 <td>39724</td>
 </tr>
 <tr>
 <td>LiPF6 in EC:DMC:DEC</td>
 <td>MTI Corporation</td>
 <td>EQ-Be-LiPF6</td>
 </tr>
 <tr>
 <td>Celgard separator</td>
 <td>Celgard</td>
 <td>C480</td>
 </tr>
 <tr>
 <td>Analog Vortex Mixer</td>
 <td>VWR </td>
 <td>58816-121</td>
 </tr>
 <tr>
 <td>Vacuum oven</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Vacuum pump</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Hydraulic press</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Coin cell case</td>
 <td>MTI Corporation</td>
 <td>EQ-CR2032-CASE-304</td>
 </tr>
 <tr>
 <td>Spring and spacer</td>
 <td>MTI Corporation</td>
 <td>EQ-CR20SprSpa-304</td>
 </tr>
 <tr>
 <td>Glovebox</td>
 <td>mBraun</td>
 <td>UNILAB</td>
 </tr>
 <tr>
 <td>Battery tester</td>
 <td>Arbin Instruments</td>
 <td>BT2143 </td>
 </tr>
 </tbody>
</table>

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.

Watch this Scientific Journal Video about Construction and Testing of Coin Cells of Lithium Ion Batteries at JoVE.com

Construction and Testing of Coin Cells of Lithium Ion Batteries

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 ...

construction-and-testing-of-coin-cells-of-lithium-ion-batteries

Research

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Engineering

31.3K Görüntüleme.  Clemson University. Lityum iyon pillerin sikke hücreleri oluşturmak ve test etmek için bir protokol tanımlanmıştır. , Bir çalışan elektrot, bir karşı elektrot hale hazırlanması, bir glovebox içindeki bir hücre montajı ve hücre test prosedürleri spesifik sunulmaktadır.

Video: Construction and Testing of Coin Cells of Lithium Ion Batteries

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 ...

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 ...

Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can potentially contribute to the exposure of biota and humans. The diffusive gradients in thin films technique is introduced here for in-situ measurements of Pu bioavailability and speciation. A diffusion cell constructed for laboratory experiments with Pu and the newly developed protocol make it possible to simulate the environmental behavior of Pu in model solutions of various chemical compositions. Adjustment of the oxidation states to Pu(IV) and Pu(V) described in this protocol is essential in order to investigate the complex redox chemistry of plutonium in the environment. The calibration of this technique and the results obtained in the laboratory experiments enable to develop a specific DGT device for in-situ Pu measurements in freshwaters. Accelerator-based mass-spectrometry measurements of Pu accumulated by DGTs in a karst spring allowed determining the bioavailability of Pu in a mineral freshwater environment. Application of this protocol for Pu measurements using DGT devices has a large potential to improve our understanding of the speciation and the biological transfer of Pu in aquatic ecosystems.

The technique of diffusive gradients in thin films (DGT) is proposed for speciation studies of plutonium. This protocol describes diffusion experiments probing the behavior of Pu(IV) and Pu(V) in presence of organic matter. DGTs deployed in a karstic spring allow assessment of the bioavailability of Pu.

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can ...

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 ...

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.

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 ...

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 ...

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 ...

Expression of Cementitious Pore Solution and the Analysis of Its Chemical Composition and Resistivity Using X-ray Fluorescence

The goal of this method is to determine the chemical composition and electrical resistivity of cementitious pore solution expressed from a fresh paste sample. The pore solution is expressed from a fresh paste sample using a pressurized nitrogen gas system. The pore solution is then immediately transferred to a syringe to minimize evaporation and carbonation. After that, assembled testing containers are used for the X-ray fluorescence (XRF) measurement. These containers consist of two concentric plastic cylinders and a polypropylene film which seals one of the two open sides. The pore solution is added into the container immediately prior to the XRF measurement. The XRF is calibrated to detect the main ionic species in the pore solution, in particular, sodium (Na+), potassium (K+), calcium (Ca2+), and sulfide (S2-), to calculate sulfate (SO42-) using stoichiometry. The hydroxides (OH-) can be calculated from a charge balance. To calculate the electrical resistivity of the solution, the concentrations of the main ionic species and a model by Snyder et al. are used. The electrical resistivity of the pore solution can be used, along with the electrical resistivity of concrete, to determine the formation factor of concrete. XRF is a potential alternative to current methods to determine the composition of pore solution, which can provide benefits in terms of reduction in time and costs.

This protocol describes the procedure to express fresh pore solution from cementitious systems and the measurement of its ionic composition using X-ray fluorescence. The ionic composition can be used to calculate pore solution electrical resistivity, which can be used, together with concrete electrical resistivity, to determine the formation factor.

The goal of this method is to determine the chemical composition and electrical resistivity of cementitious pore solution expressed from a fresh paste ...

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.

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 ...