Lithium-ion Coin Cells Research Articles

Characterization and Analysis of Coal-Derived Graphite for Lithium-Ion Batteries

Graphite is a critical material used as the negative electrode in lithium-ion batteries. Both natural and synthetic graphites are utilized, with the latter obtained from a range of carbon raw materials. In this work, efforts to synthesize graphite from coal as a domestic feedstock for synthetic graphite are reported. The performance in lithium-ion coin cells of this coal derived graphite is compared to commercial battery-grade graphite. This includes characterization of the thermodynamics of the coal derived graphite using the multi-species, multi-reaction (MSMR) model, characterization of the entropy and enthalpy of the material, and estimation of the rate capability. This enables modeling of synthetic coal-derived graphites and virtual evaluation[1] of these materials towards electric vehicle and grid storage applications.

Magnetic Force Dilatometry of Silicon-NMC622 Lithium-Ion Coin Cells: The Effects of Binder, Capacity Ratio, and Electrolyte Selection

Operando cell expansion measurements on Si-NMC622 coin cells using a magnetic dilatometer were performed to understand the effects of electrode binder content, electrode formulation, negative-to-positive electrode capacity ratio (N/P ratio), and electrolyte selection on reversible and irreversible cell expansions. Our experiments reveal a complex relationship between cell properties, imparted by the selected cell parameters, and cell expansion. Reversible cell expansions scaled with cell discharge capacity and electrode mechanical properties, while irreversible cell expansions were sensitive to capacity fade, silicon utilization, and electrolyte decomposition mechanisms. Additionally, volumetric cell energy densities were calculated using the measured capacities and irreversible expansions over the life of the cells. We show that judicious selection of cell parameters can improve volumetric energy density after 200 charge/discharge cycles by approximately two-fold. Our work provides valuable insight, at an early stage of cell development, towards minimizing the effects of cell expansion on battery cell, pack, and module designs.

Application of the Multi-Species, Multi-Reaction Model to Coal-Derived Graphite for Lithium-Ion Batteries

Graphite is a critical material used as the negative electrode in lithium-ion batteries. Both natural and synthetic graphites are utilized, with the latter obtained from a range of carbon raw materials. In this paper, efforts to synthesize graphite from coal as a domestic feedstock for synthetic graphite are reported. Domestic coal-derived graphite could address national security and energy issues by standing up domestic supply chains for battery critical materials. The performance in lithium-ion coin cells of this coal derived graphite is compared to a commercial battery-grade graphite. For the first time, a multi-species, multi-reaction (MSMR) modeling technique is applied to synthetic graphite derived from coal. Key thermodynamic, transport, and kinetic parameters are obtained for the coal derived graphite and compared to the same parameters for commercial battery-grade graphite. Modeling of synthetic graphites will allow for virtual evaluation of these materials toward production of domestically sourced graphite.

Turning the Wheel through the Ages

Methods for reliably generating alternating current via placing metal coils in a rotating magnetic field were discovered by two individuals almost simultaneously: Italian engineer and physicist, Galileo Ferraris, and Austrian-American engineer, Nikola Tesla. While Tesla attained the patent for the AC-generator, Ferraris, who published the discovery a few months prior, is credited with having paved the way for the modern-day alternator, now used ubiquitously.The origins of rotational energy conversion can be traced back to sugar plantations in the 1600s. At that time, the milling process was initially sustained through slave-driven turning of a wheel, which was geared to large wooden rollers that would squeeze sugar cane. The Caribbean and South American variant of this system was known as a trapiche, which employed three geared rollers. Over time, slaves were replaced with oxen and horses, which were eventually supplanted by water wheels and finally by steam engines. The water wheels implemented for sugar milling ultimately paved the path for creating electrical currents. Water turbines for hydroelectric power subsequently took off. Principles of steam engine operation were adapted for electrical power as well, ultimately culminating in the use of nuclear plants to generate “wheel” turning for electricity.Electricity and magnetism, as well as interactions between them, are frequently discussed in introductory undergraduate physics. However, practical applications of these principles are often omitted from lectures. If taught under an experiential environment, these concepts can be introduced at even the middle school level, taught by first year college students taking basic college physics - a synergistic learning environment. With this in mind, we developed a middle school kit consisting of simple 3D-printed components, recycled DVDs and four bearings for support of 4 mm nail shafts. Enameled wire (30 AWG) is used to prepare the wire-wound coils. A large rubber band is used as the pulley-belt. The above represents the generator component. The power use component is assembled on an accompanying bread board. Power processing is demonstrated using diodes for rectification to DC. The DC power is used to recharge a 3V, 40 mAh lithium-ion coin cell. AC power from the generator can also be directly applied to load resistors. Students will be able to see the effects of varying the load by changes in the time of the free rotation of the generator wheels. Students will experience the charge and discharge of batteries with safe voltages and currents.Middle school students will record data from the generator and conditioning systems and draw conclusions on worksheets that accompany the hardware.

Design and fabrication of low-cost renewable carbon electrode materials and their thermo-kinetics for sustainable energy storage applications

Low-cost, abundant biomass is a promising raw material for future applications in energy storage when processed into renewable graphitic carbon. To date, there have been few studies performed on the kinetics of thermal decomposition of renewable carbon and its use in energy storage devices. Novel renewable graphitic carbon from Acer saccharum, sugar maple (SM) heartwood, and Arachis hypogaea, peanut outer shell (PS), are used as anodes in lithium-ion coin cell batteries, with steady specific capacities of 180 mAh/g and 220 mAh/g, respectively, and both retain 100% columbic efficiency for over 350 cycles. Cyclic voltammetry reveals the different charge storage kinetic mechanisms of the two. The voltammogram of SM contains an oxidation peak indicating Li ion intercalation suitable for battery application, while PS lacks a peak; thus, showing potential for function as a supercapacitor. A kinetic study is undertaken on six carbon sources to improve the understanding of the thermal degradation process leading to renewable graphitic carbon. Consistent results are shown across the various model-free methods, indicating that they can accurately describe the devolatilization process. The renewable graphitic carbons morphological features were studied by SEM, XRD, Raman and nitrogen adsorption isotherms. As SM and PS compare favorably to the electrodes they replace, renewable graphitic carbon has the potential for use in a wide variety of novel applications, such as organic thin film transistors, fuel cells, organic batteries, supercapacitors, and other bioelectronics.

Impedance-based forecasting of lithium-ion battery performance amid uneven usage

Accurate forecasting of lithium-ion battery performance is essential for easing consumer concerns about the safety and reliability of electric vehicles. Most research on battery health prognostics focuses on the research and development setting where cells are subjected to the same usage patterns. However, in practical operation, there is great variability in use across cells and cycles, thus making forecasting challenging. To address this challenge, here we propose a combination of electrochemical impedance spectroscopy measurements with probabilistic machine learning methods. Making use of a dataset of 88 commercial lithium-ion coin cells generated via multistage charging and discharging (with currents randomly changed between cycles), we show that future discharge capacities can be predicted with calibrated uncertainties, given the future cycling protocol and a single electrochemical impedance spectroscopy measurement made immediately before charging, and without any knowledge of usage history. The results are robust to cell manufacturer, the distribution of cycling protocols, and temperature. The research outcome also suggests that battery health is better quantified by a multidimensional vector rather than a scalar state of health.

Impedance-based capacity estimation for lithium-ion batteries using generative adversarial network

This paper proposes a fully unsupervised methodology for the reliable extraction of latent variables representing the characteristics of lithium-ion batteries (LIBs) from electrochemical impedance spectroscopy (EIS) data using information maximizing generative adversarial networks. Meaningful representations can be obtained from EIS data even when measured with direct current and without relaxation, which are difficult to express when using circuit models. The extracted latent variables were investigated as capacity degradation progressed and were used to estimate the discharge capacity of the batteries by employing Gaussian process regression. The proposed method was validated under various conditions of EIS data during charging and discharging. The results indicate that the proposed model provides more robust capacity estimations than the direct capacity estimations obtained from EIS, where the mean absolute error and root mean square error are less than 1.74 mAh and 1.87 mAh, respectively, for all operating conditions for lithium-ion coin cells with a nominal capacity of 45 mAh. We demonstrate that the latent variables extracted from the EIS data measured with direct current and without relaxation reliably represent the degradation characteristics of LIBs.

Electrochemical performances of lithium-ion coin cell based on Li4Ti5O12 anode

Recently many portable devices need electrical energy which instant and high capacity. Lithium-ion battery is one of very popular as mobile electrical energy source for them. This experiment focused to elaborate the electrochemical performances of Lithium-Ion (LI) coin cell based on Li4Ti5O12 (LTO) Anode with variation of calcination holding time (2, 4 and 6 hours) at temperature 900°C. They are electrical conductivity, specific capacity and coefficient of ion diffusion. Sol-Gel method and doctor Blade technique were used to produce LTO anode material. Vacuum technique was used to assembly LI coin cell. Electrochemical Impedance Spectroscopy and Cyclic Voltammetry were used to measure the electrochemical performances of theses coin cells. The best result of these experiments showed that coefficient of ionic diffusion is 3.48×10−4 cm2/S, the specific capacity value is 304 mAh/g and electrical conductivity value is 6.87×10−3 S/cm. So, this experiment has shown strongly a prospective for application in the future to produced commercially lithium-ion coin cells.

Fabrication of Rechargeable Lithium Ion Coin Cell using Triblock Polymer Electrolyte Poly (Vinylidene Chloride-Co-Acrylonitrile- Co-Methyl Methacrylate) with Lithium Perchlorate

Fabrication of Rechargeable Lithium Ion Coin Cell using Triblock Polymer Electrolyte Poly (Vinylidene Chloride-Co-Acrylonitrile- Co-Methyl Methacrylate) with Lithium Perchlorate

Investigation of Electrochemical, Thermal and Electrical Performance of 3D Lithium-Ion Battery Module in a High -Temperature Environment

In the present time, the rechargeable lithium-ion battery is being commercialized to meet the sustained market’s demands. To design a more reliable, safe, and efficient Li-ion battery, a 3-D simulation study has been presented in this paper. In this study, a lithium-ion coin-cell is proposed which has LiFePO4 as a positive electrode with a thickness of 1.76 µm, carbon as a negative electrode with a thickness of 2.50 µm and Celgard 2400 polypropylene sheet as a separator between the electrodes with a thickness of 2 µm. The proposed Li-ion battery has been designed, analyzed, and optimized with the help of Multiphysics software. The simulation study has been performed to analyze the electrochemical properties such as cyclic voltammetry (CV) and impedance spectroscopy (EIS). Moreover, the electrical and thermal properties at the microscopic level are investigated and optimized in terms of surface potential distribution, the concentration of electrolyte, open circuit, and surface temperature with respect to time. It has been noticed that the peak voltage, 3.45 V is observed as the temperature distribution on the surface varies from 0 OC to 80 OC at a microscopic scale with different C-rates. The analysis of simulation results indicates a smoother electrode surface with uniform electrical and thermal properties distribution resulting in improved reliability of the battery. The performed simulation and optimization are helpful to achieve control over battery performance and safe usage without any degradation of the environment.

Influence of charge conditions on battery dynamics of a commercial lithium-ion cell

Electrochemical impedance spectroscopy measurements were performed to determine the effect of the state-of-charge, charge current, and current-drop time on battery dynamics of a commercial 2032 lithium-ion coin cell. The impedance response was systematically investigated and discussed by using the Taguchi design. The results showed that the state-of-charge had a statistically significant effect on both the resistance for solid electrolyte interphase formation and cathodic charge transfer resistance. It was showed that the Taguchi design is a valuable tool for analyzing battery dynamics obtained through the equivalent circuit model. The Taguchi design opened the door for a robust design of lithium-ion batteries in real life.

Higher Voltage, Wider Voltage Plateau, Longer Cycle Life, and Faster Kinetics Via Thermally Modulated Interfaces between Ramsdellite and Pyrolusite MnO2 for Lithium-Ion Battery Cathodes

The cathode for Lithium-ion batteries is dominated by transition metal oxides that exist in numerous polymorphic structures. To emphasize generality and the underpinnings of thermodynamics in the stability, activity, and kinetics of lithiation, we utilize the nomenclature of the native structure and non-native structure for referring to different transition metal oxides polymorphic structures. The native structure is the thermodynamic ground state (bulk phase) structure and various non-native structures have different discrete translational symmetry in their sub-surface regions compared to the native structure. Typically, non-native structures have higher (i.e. less negative) bulk formation energy and more open structures than the native structure. Hence, non-native structures are expected to generate higher discharge potential and better lithium mobility as a positive electrode material. However, non-native structures may be limited in stability, which can be increased by scaffolding them with the native structure. To explore these hypotheses, we synthesize pure Ramsdellite MnO2 (r/NN1-MnO2) and thermally phase transform it gradually to Pyrolusite MnO2 (β/N-MnO2) and intimately interfaced (r/NN1-MnO2)/(β/N-MnO2) intergrowth structures are obtained. As the temperature increases, the ratio of r/NN1-MnO2 to β/N-MnO2 in the intergrowth structure decreases; so does the discharge potential and lithium mobility in the lithium-ion coin cell. In addition, the galvanostatic discharge profile shows a wider discharge plateau for intergrowth structures as compared to the pure native and non-native structure. We rationalize these trends in discharge potential using formation energies computed via density functional theory followed by a statistical averaging to account for the different types of lithium intercalation sites in the intergrowth structures. The wider discharge plateau in the intergrowth structure is rationalized with the presence of additional interfacial sites of higher stability than the site available in single phase native and non-native structure. The capacity retention is higher for the intergrowth structure, which is ~64% compared to ~42% and ~32% as obtained for pure native and non-native structures after 100 cycles at a rate of 0.1C. The improved capacity retention for intergrowth structure is due to higher structural stability and available free volume, where the presence of native structure acts as a scaffold to stabilize the non-native structure. The electrochemical impedance spectroscopy suggests that the larger percentage of non-native structure helps in better transport due to greater free volume present in r/NN1-MnO2 structure with wider 2×1 channel compared to the native structure with the narrow 1×1 channel. This study demonstrates how a systematic control of the relative percentage of each phase, without change in chemical composition, helps in designing cathodes with improved capacity and cycle life, thereby expanding the available material space.

A Methoxyamine-Protecting Group for Organic Radical Battery Materials-An Alternative Approach.

An alternative synthetic route towards the widely employed electroactive poly(TEMPO methacrylate) (PTMA) via a thermally robust methoxyamine-protecting group is demonstrated herein. Protection of the radical moiety of hydroxy-TEMPO with a methyl functionality and subsequent esterification with methacrylic anhydride allows the high-yielding formation of the novel monomer methyl-TEMPO methacrylate (MTMA). The polymerization of MTMA to poly(MTMA) (PMTMA) is investigated via free radical polymerization and reversible addition-fragmentation chain-transfer polymerization (RAFT), a reversible-deactivation radical polymerization technique. Cleavage of the temperature-stable methoxyamine functionality by oxidative treatment of PMTMA with meta-chloroperbenzoic acid (mCPBA) releases the electroactive PTMA. The redox activity of PTMA was confirmed by cyclic voltammetry in lithium-ion coin cells.

In situ X-ray spatial profiling reveals uneven compression of electrode assemblies and steep lateral gradients in lithium-ion coin cells.

Coin cells are used extensively as test devices in battery research for evaluation of new materials and optimization of cycling protocols. In this study, in situ X-ray diffraction profilometry is used to characterize spatial distribution of the active materials, lithiation, and phase distribution in electrodes of NCM523/graphite coin cells. The X-ray data indicate uneven areal compression of the electrode assembly in such cells, which we trace to a specific design feature that leads to elastic deformation of a metal spacer. Steep lithiation gradients observed in the electrodes imply radially-dependent resistivity, for which uneven compression of the separator is a likely cause. Electrochemical model calculations suggest that variable porosity of the polymer separator would account for the salient features of spatial profiles observed in these coin cells.

Neutron tomography study of a lithium-ion coin battery

Neutron imaging of lithium-ion coin cell battery was obtained using tomography technique at Neutron Scattering Laboratory in Multi-Purpose Research Reactor G. A. Siwabessy (RSG-GAS) Serpong facility. The coin cell battery was CR2032 (20d x 3.2t mm) type consisted of positive and negative cases made of stainless steel, a cathode layer from lithium Ferro phosphate coated on aluminum foil, polyethylene film as separator, lithium hexafluorophosphate solution in ethylene carbonate and diethyl carbonate as electrolyte, an anode layer from graphite coated on copper foil, and spacer as well as spring made of stainless steel. The neutron tomography was used to observe the inside structure of the full charged coin cell. The observation was carried out with a neutron flux of 107 n/s.cm2 at 15 MWatt of reactor power. The image of the object is obtained by a Charge Coupled Detector (CCD) and the reconstruction software based on a filtered back-projection algorithm. The neutron imaging clearly shows the cell structure inside the casing. Even though the cell is not at the center of the casing, but it appears that the cell component consists of a cathode, separator and anode neatly arranged. The cross-cut image shows the important role of spring and spacer in improving the contact between cell and casing. The results showed the ability of neutron tomography techniques at RSG-GAS to investigate in detail the inside structure of a coin battery without disassembly (non-destructive test).

Utilization of Petroleum Coke Soot as Energy Storage Material

Anode active materials for lithium ion batteries (LIBs) were produced by using waste soot generated after combustion in a plant using petroleum coke as fuel. The soot collected from the boilers in the plant was graphitized through annealing, and this annealed soot was applied to anode active materials. After annealing at 2700 °C, the soot was converted into highly crystalline graphite with ring shapes approximately 100 nm in diameter. The lithium ion coin cells produced using graphitized soot showed high discharge capacity and excellent life cycle with a reversible capacity of 250 mAh/g even after 300 cycles at a rate of 1 C. This study describes a new possibility of using environmentally harmful combustion wastes of petroleum coke as a low-price anode material for LIBs by converting them into a graphite multilayer structure with a unique ring shape through annealing.

Highly efficient gel polymer electrolytes for all solid-state electrochemical charge storage devices

Gel polymer electrolytes are prepared using poly(vinylidene fluoride-co-hexafluoropropylene) polymer matrix and 1- propyl-3-methyleimidazolium bis(trifluromethylesulfonyl)-imide ionic liquid and also by adding lithium bis(trifluoromethanesulfonyl)imide salt and plasticizer mixture (ethylene carbonate: propylene carbonate in the ratio 1:1). Thermal and electrical properties of these electrolytes are first investigated. The electrical conductivity of these electrolytes is analyzed over a wide frequency range using a universal power law coupled with modified Poisson-Nernst-Planck model for electrode polarization. All electrolytes show excellent thermal stability up to 340 °C, high ionic conductivity (∼1 × 10−3 S cm−1) and wide potential window (∼4.0 V). Supercapacitors are fabricated with these electrolytes using activated carbon as electrodes and their electrochemical properties are studied. The cyclic voltammetry curves show almost box-like shape corresponding to an ideal and reversible capacitive characteristic. The specific capacitance of supercapacitors increases with the addition of lithium salt and plasticizer mixture. The cycle stability of these supercapacitors up to 4000 cycles confirms their electrochemical stability. A lithium ion coin cell is also fabricated using electrolytes containing plasticizer mixture. At ambient temperature, the fabricated cell delivers high specific discharge capacity (∼165.8 mAh g−1) for the first discharge cycle at a constant current rate C/12.

The Influence of Surface Morphology of Copper Foils on the Efficiency of Lithium Ion Batteries

For the increasing demand of portable electronic devices and electric vehicles, lithium-ion batteries (LIBs) become a fast-growing and crucial technology because of high power density and light weight. To manufacture LIBs with good performance and appropriate cost, the components constituting LIBs should not only possess excellent quality and reliability but also be cost-effective. The current collector in the negative electrode of LIBs is an indispensable material, and the most commonly used material is copper foil with optimal quality. Currently, the mainstream copper foil adopted in LIBs is manufactured by rolling, since the rolled copper foil provides smooth surfaces on double sides (Rz < 1 μm), which ensure good capacity retention rate. However, the rolled copper foil is much more expensive than electrodeposited (ED) copper foil, especially for ultra-thin one (< 8 μm), since it requires more times of rolling and annealing. Consequently, the manufacture of thin ED copper foil with optimal properties is a critical issue to lower the cost of LIBs. Unfortunately, the ED copper foil produced by conventional method is not applicable in LIBs industry, and the main reason is that the surface roughness of the ED copper foil on both sides is remarkably different, which affects the capacity retention rate of LIBs [1]. In addition, the actual mechanism of how the surface morphology influencing the performance of LIBs has been not studied yet. In this work, we produced an 8 μm thick ED copper foil with different surface morphology by adding specific additives in the plating bath, including very low profile copper foil (Rz < 0.1 μm) or copper foil with pinholes on the surface, and comparing the performance of these ED copper foils with a conventional ED copper foil and a commercial rolled copper foil. The surface morphology and structure of each copper foil was examined by SEM, AFM, and XRD. Most importantly, carbon based material would be coated on these copper foils and then sealed in coin cells to examine the electrochemical behavior and efficiency of lithium ion coin cells. Accordingly, the relationship of the active carbon material and the surface morphology of the negative current collector was clarified. Reference : 1. Kazuo Kondo, Rohan N. Akolkar, Dale P. Barkey, Masayuki Yokoi, Copper Electrodeposition for Nanofabrication of Electronics Devices, p. 243, Springer-Verlag New York (2014).

A Metal‐Free and Biotically Degradable Battery for Portable Single‐Use Applications

This article presents a new approach for environmentally benign, low‐cost batteries intended for single‐use applications. The proposed battery is designed and fabricated using exclusively organic materials such as cellulose, carbon, and wax and features an integrated quinone‐based redox chemistry to generate electricity within a compact form factor. This primary capillary flow battery is activated by the addition of a liquid sample and has shown continuous operation up to 100 min with an output voltage that can be conveniently scaled to match the voltage needs of portable electronic devices (1.5–3.0 V). Once depleted, the battery can be disposed of without the need for any recycling facility, as its components are nontoxic and shown to be biotically degradable in a standardized test. The practical utility of the battery is demonstrated by direct substitution of a lithium ion coin cell in a diagnostic application.

High energy lithium ion battery electrode materials; enhanced charge storage via both alloying and insertion processes

A series of nano-sized tin-doped metal oxides of titanium(IV), niobium(V) and vanadium(IV), were directly synthesized using a continuous hydrothermal process and used for further testing without any post-treatments. Each of the as-prepared powders was characterized via a range of analytical techniques including powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Brunauer-Emmett-Teller surface area measurements, as well as being investigated as an electrode material in a lithium-ion coin cell (vs lithium metal). All the tin-doped nanomaterials showed higher specific capacities compared to their undoped metal oxide counterparts. The increased charge storage was discussed to originate from the electrochemical activation of the tin dopant as an alloying material. Overall, this work presents a reliable method of combining stable insertion materials with high capacity tin alloying materials under scaled-up conditions.