Li O2 Cathode Research Articles

Thermal abusive experimental research on the large-format lithium-ion battery using a buried dual-sensor

The study on the thermal flow characteristics of temperature and pressure is helpful to understand the thermal runway mechanism of batteries. In this study, a 50 Ah, 3.65 V commercial prismatic battery with an Li(Ni0.6Co0.2Mn0.2)O2 cathode is tested through thermal abusive experiments. The thermal flow characteristics of thermal runaway behaviors including temperature, pressure and gas quality have studied comprehensively by the proposed method of a dual-sensor, which are buried into battery. The experimental results indicate that the thermal runaway test can be divided into five stages. The internal pressure reaches to its maximum value of 1230 kPa and the first venting of the battery is appeared during Stage Ⅲ. During Stage Ⅴ, the battery internal temperature reaches to the maximum value of 655℃, and the second venting happens. The maximum pressure appears 290s earlier than temperature in average, which can be used for warming signal. Additionally, before battery safety valve bursting, its internal pressure variation has interactions with changings in both temperature and the amount of chemical reactant. To analyze this relationship, the P-T coefficient is introduced. The P-T coefficient is positive in the temperature ranges of 30 ℃ to 65 ℃, 95℃∼ 115 ℃and 130 ℃∼ 180 ℃. This means that the internal pressure of battery increases with temperature rising, which is mainly due to the reaction gas production. In the temperature of 65 ℃∼95℃, the P-T coefficient is negative. It can be deduced that the produced reactants, such as alkanes and alkenes, are re-dissolved in the organic electrolyte solvents. In summary, this novel study will be a guidance for thermal hazards early warming and battery internal thermal state analysis, which guides the thermal safety design of batteries.

Gradient-Regeneration of Li(Ni0.9Co0.05Mn0.05)O2 from Spent LiCoO2 lithium-Ion Battery

Considering that lithium-ion battery (LIB) is still an indispensable and important component of energy storage materials, the sustainable post-processing of spent LIBs in labs or enterprises becomes a tricky problem. Herein, a novel scheme is proposed to dissert the recycling of the spent LIBs. The LIB is recycled into Li(Ni0.9Co0.05Mn0.05)O2 (NCM90) cathode material with high specific capacity by introducing an innovative hydrometallurgy-coprecipitation treatment method. The spent LiCoO2 (LCO) cathode material is firstly leached by sulfuric acid, and the leachate is gradient used as the raw materials to resynthesize high-nickel NCM material by adjusting the leachate dosage to about 50%. Interestingly, when the dosage exceeds 50%, the crystal structure aggravates, and Li+/Ni2+ mixing improves. The specific capacity of regenerated battery is 181.4 mAh g−1 at 0.5 C (1 C = 200 mAh g−1) and the capacity retention achieves 93.2% after 100 cycles. The reasons can be attributed to the cation mixing and crystal strucure and the small amount of Al doping. In conclusion, this combined method recycling of LIBs has huge potential value for environment protection and production.

Redox Synthesis and Characterization of Layered LiNi1/3Co1/3Mn1/3O2 for Rechargeable Lithium Ion Batteries

This study reports on the characterization of layered Li (Ni1/3Co1/3Mn1/3)O2 (x = 1.05 and 1.1) cathodes synthesized by a simple ambient temperature redox synthesis and post-heat treatment with added lithium sources.Synchrotron XANES and ICP measurements were performed to confirm the change in oxidation state during the redox reaction and the successful control of the stoichiometric ratio of ternary transition metal oxides (Ni2+ 0.33Co3+ 0.35Mn4+ 0.32Oy).In the FE-SEM image, loosely aggregated particles with an average diameter of 60nm appeared in the intermediate product, and the particle size grew to several hundred nanometers after lithiation at elevated temperature.The electrochemical performances at 14 mAg-1 in the potential range of 3.0–4.3V vs. Li/Li+ indicated that reasonable specific capacities and cycle performances are registered for all the prepared cathodes. especially, the Li1.05(Ni1/3Co1/3Mn1/3)O2 composition demonstrated the highest capacity retention value (~99%) after 50 cycles and better rate performances (104, 91, 76, and 67 mAhg-1) at high current densities (229, 457, 914, and 1429 mAg-1 respectively).

An Experimental Study on Thermal Runaway Behavior for High-Capacity Li(Ni0.8Co0.1Mn0.1)O2 Pouch Cells at Different State of Charges

Abstract Lithium-ion cells normally operate during 0% and 100% state of charge (SOC), therefore thermal runaway can occur at any SOC. In this paper, the 74 Ah lithium-ion pouch cells with the Li(Ni0.8Co0.1Mn0.1)O2 cathode were thermally abused by lateral heating in a semi-open chamber. The differences of thermal runaway behavior were investigated under six SOCs. Characteristic parameters such as triggering time and triggering temperature for thermal runaway show a negative correlation with SOCs, while maximum surface temperature and maximum surface temperature rise rate show a strongly positive correlation. Besides, mass loss ratio increases exponentially with equivalent specific capacity statistically, which implies that the pouch cells with high specific energy density and high capacity may eject more violently. Furthermore, the impact on the surroundings caused by high-temperature ejections was studied, and maximum ambient temperature and maximum ambient pressure in the chamber reached a plateau at middle SOCs. Based on the thermal impact on the surroundings, a theoretical method is proposed to evaluate the deterioration of heat dissipation by venting, and simplified to quantitatively calculate the deterioration under above SOCs. The results can provide guidance for battery safety management strategies and structure design of the battery pack.

Effect of calcium or yttrium doping on cation ordering and electrochemical performance of Li(Ni0.80−xCo0.15Al0.05Mx)O2 (M = Ca, Y) as a Li-ion battery cathode

The electrochemical performance of Li(Ni0.80Co0.15Al0.05)O2 (NCA) cathode was demonstrated to be improved by calcium and yttrium doping. Samples were synthesized by ultrasonic sound-assisted co-precipitation method which satisfied precipitation of nano-sized particles around 20 nm. Doping elements were introduced to the structure by solid-state reaction route and single phase, layered Li0.993(Ni0.804Co0.154Al0.035Y0.014)O2±σ and Li0.991(Ni0.801Co0.152Al0.037Ca0.019)O2±σ samples were successfully synthesized. Lattice parameters and site occupancy of the atoms were calculated by Rietveld refinement. Occupancy refinement of the atomic sites confirmed that doping elements occupied the transition metal layer as it was aimed. The presence of doping elements in the transition metal layer stabilized nickel and decreased the amount of cation mixing. Y-doped NCA sample exhibited the highest initial specific discharge capacity (157 mAh g−1) and Ca-doped sample showed the highest rate capability. Pristine NCA showed the lowest capacity, in any case, indicating the necessity of further treatment to achieve improvement in NCA cathode.

Graphene-based nanocomposite cathodes architecture with palladium and α-MnO2 for high cycle life lithium-oxygen batteries

High-efficiency electrocatalysts of palladium and α-MnO2 nanowires supported on reduced graphene oxide (rGO) sheets are developed through an effective process to enhance the electrochemical performance of current lithium-oxygen batteries. Palladium is known as an oxygen evolution reaction (OER) electrocatalyst in Li–O2 cathode to reduce the charge overpotential and exhibit stable cycling performance. On the other hand, MnO2 is an attractive, functional transition metal oxide catalyst in Li–O2 batteries due to its low cost, high catalytic activity, and good oxygen reduction behavior. This study integrates the synergic effects of α-MnO2 nanowires and palladium nanoparticles by decorating on graphene sheets to improve cyclability and capacity to obtain highly efficient performance of Li–O2 cells. As-prepared rGO/Pd/α-MnO2 hybrid nanocomposite cathode indicates an initial discharge capacity of 7500 mA h g−1 and stable cycle life for 50 cycles at a limited capacity of 800 mA h g−1. As a result, although the polarization of the cell dramatically decreases and stable capacity behavior is observed with the contribution of α-MnO2 and Pd catalysts, the limited stable cycle life of 50 is obtained due to the consumption of lithium metal which causes total capacity failure after 60 cycles.

Synergistic effect of Ce4+ modification on the electrochemical performance of LiNi0·6Co0·2Mn0·2O2 cathode materials at high cut-off voltage

Ni-rich layered LiNi0·6Co0·2Mn0·2O2 materials have recently drawn much attention for their high specific capacity. However, they still suffer from the cycling instability arising from Li+/Ni2+ ions mixing in crystal structure and harmful side reactions with electrolyte, especially charged at high cut-off voltage to achieve higher energy density. In this study, the Li(Ni0·6Co0·2Mn0.2)O2 (NCM622) cathode materials were prepared by sol-gel method, and Ce4+ modification was utilized to improve cycling stability and rate performance. Through XRD refinement, XPS, SEM and TEM characterization, it was found that in the case of 0.5 at% level, Ce4+ ions not only entered into the crystal lattice to replace transition metal ions, but also produced CeO2 coating on the surface of NCM622 particles. The results of electrochemical performance showed that after 100 cycles at 1 C rate, the capacity retention of NCM-0.5 sample increased by 11.03% compared to pristine sample. Besides, in the case of 5 C, the capacity of NCM-0.5 sample reached to 114.92 mAh·g−1, much higher than that of NCM-0 (91.92 mAh·g−1). The findings indicate that it is the synergistic effect of Ce4+ that endows NCM622 excellent cycling stability and rate performance at high cut-off voltage.

Lithium-ion (de)intercalation mechanism in core-shell layered Li(Ni,Co,Mn)O2 cathode materials

Abstract LiNixCoyMn1-x-yO2 (NCM) intercalation compounds with core-shell architecture have been found to be promising cathode candidates for next-generation lithium-ion battery applications. The NCM cathodes' functional properties are dependent on the transition metal relative ratios, making it a challenge to control the real structure of core-shell NCM cathode materials and to understand the synergistic effect of core and shell during the electrochemical cycling. Herein, a universal and facile synthetic strategy is developed to synthesize the NCM material composed of an inner Ni-rich core and a Mn-rich shell on a secondary particle level. Both the Ni-rich particle core and the Mn-rich outer surface possess a layered α–NaFeO2–type structure with the same space group (R 3 ‾ m). The in situ synchrotron-based X-ray diffraction and absorption spectroscopy results demonstrate that the two layered phases do not participate in the electrochemical reaction simultaneously during the first cycle between 2.7 and 4.3 V, while they exhibit a similar reversible (de)lithiation mechanism in the following cycles. These findings provide a new perspective for rational design of layered Ni-based cathode materials with high energy and long cycling life with particular two phase electrochemical characteristics.

Electrochemical performance of a Ni0.8Co0.15Al0.05LiO2 cathode for a low temperature solid oxide fuel cell

The electrochemical performance of the Ni0.8Co0.15Al0.05LiO2 (NCAL) cathode was investigated by comparing it with the traditional La0.4Sr0.6Co0.2Fe0.8O3-δ (LSCF) and LSCF/Ce0.9Gd0.1O2-δ (GDC) cathodes with a GDC electrolyte-supported solid oxide fuel cell (SOFC). It is found that the electrochemical performance of the cells with the NCAL and NCAL/GDC cathode is better than that of the cells with the LSCF and LSCF/GDC cathode at 550 °C. The results of the electrochemical performance tests of the cells with different NCAL/GDC mass ratios (10/0, 9/1, 8/2, 7/3 and 6/4) show that the NCAL/GDC composite cathode with the mass ratio of 8/2 has the best electrochemical performance. XRD results show that when the sintering temperature is higher than 700 °C, the NCAL/GDC composite will undergo chemical reactions and generate new phases, reducing the performance of the composite cathode. XPS results show that a small amount of Li2CO3 was formed on the surface of NCAL during cathode preparation, forming a special interface between NCAL, Li2CO3 and GDC. At the NCAL-Li2CO3/GDC interfaces, due to the migration and aggregation of Li+ to the interface, a space charge region may be formed in which the Li+ enrichment may lead to the formation of the region with a high oxygen vacancy concentration. A very high oxygen vacancy concentration at the NCAL-Li2CO3/GDC interfaces will provide sufficient oxygen ion conductivity for oxygen reduction reaction (ORR) and reduce the activation energy of the reaction. NCAL will be a potential cathode material that can reduce the operating temperature of the traditional SOFC to 550 °C or lower.

Effects of surface modification and organic binder type on cell performance of water-processed Ni-rich Li(Ni0.8Co0.1Mn0.1)O2 cathodes

The Ni-rich Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) is surface-modified using phosphoric acid (HPO) and silane reagents, and water-based cathode slurries of unmodified and modified NCM811 are prepared with poly(acrylonitrile) (PAN) or poly(acrylic acid) (PAA) added as the binder to compare the electrochemical performances of the constructed cells. Surface modification using HPO or the addition of PAA as the binder can substantially reduce the alkalinity of the prepared aqueous slurry of NCM811, thereby preventing the slurry from corroding the aluminum current collector, as well as retaining the good structural integrity of the dried electrode. The aforementioned advantage about the reduction in the alkalinity is not achieved when the hydrophobic silane-modified NCM811 or the neutral binder PAN is used. The best cell performance in terms of electrochemical reversibility, ionic and electronic impedance, and cycle stability is obtained when the water-based cathode slurry is prepared using HPO-modified NCM811 as the cathode active and PAA as the binder simultaneously. Moreover, the addition of PAA rather than the adoption of HPO-modified NCM811 contributes more to the improvement of cell performance.

Overcharge investigation of degradations and behaviors of large format lithium ion battery with Li(Ni0.6Co0.2Mn0.2)O2 cathode

Abstract Overcharge is considered to be one of the most severity safety problems for large format lithium ion battery (LIB), understanding of correlation between overcharge states and associated degradations is still a challenging issue. Here overcharge features of 51Ah prismatic LIBs were studied by charging the LIBs to various state of charge (SOC). When the SOC reaches up to 125%, lithium plating and lithium involved side reactions have taken place accompanied by capacity fade, internal resistance increase and LIB swelling. Meanwhile, the interlayer spacing of graphite anode is enlarged as indicated by shift of (002) diffraction peak to lower angle. When the SOC reaches up to 140%, additional to above reactions aggravation, structural damage of cathode materials was found. With further increase of SOC, internal side reactions became more violent as indicated by obvious self-heating at 146% SOC. Moreover, effects of charging current and initial temperature on overcharge behaviors were also discussed. Large charging current (4C) can lead to more severity thermal runaway as supported by higher maximum surface temperature of 413.34 °C compared to that of 187.90 °C at 1C. LIB overcharged at initial low temperature shows quick temperature rise but lower maximum surface temperature of 143.15 °C at 160% SOC compared to that of 187.90 °C at 159% SOC for LIB overcharged under ambient temperature

A scalable approach of using biomass derived glycerol to synthesize cathode materials for lithium-ion batteries

Glycerol, a main byproduct of biodiesel, was used as the fuel agent in a scalable flame-assisted spray pyrolysis approach to synthesize micron-size cathode materials. Single droplet combustion, particle morphology, and electrochemical performance were examined considering the effects of salt concentration, water addition, and post-annealing time on synthesizing Li(Ni1/3Co1/3Mn1/3)O2 (NCM111) cathode materials. Single droplet tests showed that a sufficient amount of water in the glycerol-based precursor could delay droplet inflation and ignition. Moreover, using a two-fluid atomization nozzle, spray tests demonstrated that adding water would result in less wrinkled and more uniform particles. Nevertheless, increasing water proportion in the precursor could reduce the reaction heat, resulting in that samples prepared with water addition needed longer post-annealing time to improve their electrochemical performance. Using the precursor without water, the best performed NCM111 cathode material was synthesized with only 2 h of post-annealing. It has a discharge capacity of 163.3 mAh/g at 0.1C and 85.5% capacity retention at 1C after 100 cycles. The current work confirmed the capability of using glycerol as a sustainable fuel agent to synthesize NCM111 cathode materials, and also provided basic conditions for the development of large-scale production in the future.

Quantitative analysis of eruption process of abused prismatic Ni-rich automotive batteries based on in-chamber pressure

Lithium-ion battery (LIB) eruptions play an important role in battery fires in electric vehicles. This study aims to quantitatively reveal the eruption process of LIBs. A 50-Ah commercial prismatic cell with a Li(Ni0.6Mn0.2Co0.2)O2 cathode was triggered to thermal runaway using external heating in a sealed chamber with different initial nitrogen atmospheres under 0%, 25%, 50%, 75%, and 100% state of charge (SOC) values, respectively. Based on the in-chamber pressure under 100% SOC value, a quantitative analysis method for the LIB eruption process was proposed, and applied to the other SOC values at different test conditions. Results show that using a LIB eruption index (i.e., product of the in-chamber pressure rise rate and the cubic root of the chamber volume) based on the gas explosion index can effectively and quantitatively analyze the LIB eruption process at 100% SOC. According to the variation of the explosion indices with time, LIB eruption processes can be divided into ultrafast, fast, and slow phases. This quantitative analysis method is also effective in case of the eruption process at different SOC values under different conditions. Thus, the results of this study can provide guidance for fire early warning systems, fire suppression strategies, proper battery selections, and storage designs.

Achieving Stable Cycling of Li-Metal Anodes in Li-O2 Batteries: Optimizing Solvation Environment in Ionic Liquid/Solvent Blend Formulations

The realization of a truly rechargeable, high capacity lithium-oxygen (Li-O2) battery faces serious technological barriers relating to material/intermediate stability, electrochemical reversibility of the cathode discharge processes, and gas supply challenges.1 Furthermore, to maximize energy densities of Li-O2 cells, the utilization of Li-metal anodes is highly desired, thus introducing additional and serious interfacial challenges in the form of electrolyte degradation and susceptibility to dendrite formation on cycling. These factors ultimately create serious safety issues and further contribute to the reduced cyclability of Li-O2 cells that is already limited by the poor reversibility of Li2O2 formation at the cathode. Without introducing artificial anode protection or isolation of Li from a cathoylte compartment, the electrolyte for a high-performance Li-O2 device must exhibit complementary stability at both reactive interfacial regions of the two different electrodes. In many cases, the solvents that mediate good performance at the Li-O2 cathode exhibit poor stability at Li-metal and, consequently, new electrolyte formulations geared towards good stability and performance at both the cathode and the anode are required.In this work, we report on the development of blend electrolytes of ionic liquids (ILs) and molecular solvents for improving cell performance in Li-O2 batteries with considered focus on enhancing stability at the Li-metal anode. Through combined experimental and theoretical investigations, we present how the electrochemical stability of Li-O2-cathode relevant molecular solvents at the Li-metal anode can be regulated by tuning formulation properties. Wide formulation ranges, including dilute to highly concentrated Li-salt mixtures are explored within the ternary formulations of IL, molecular solvent and Li-salt. Good performance in symmetrical Li|electrolyte|Li cells is achieved through improving the Coulombic efficiency of the electroplating/stripping processes, as quantified in asymmetric Li|Cu cells. In lieu of strong SEI forming additives, these observed stability enhancements are found to be highly reliant on Li+-solvent solvation interactions within the liquids. Shifts in vibrational modes associated with changes in coordination, as measured by Raman and IR spectroscopy, provide insights into the nature of these important solvent and salt interactions. These experimental insights are supported by computational modelling of local solvation environments in select exemplary mixtures. Pulsed-field gradient NMR techniques are also utilized to understand what information the diffusional motion of differing species within the IL/solvent blends further reveals about the nature of these stabilizing coordination interactions. The implications of complete formulation design towards achieving mutual stability at anode and cathode interfaces is demonstrated within full cell (Li-O2) testing using composite air-cathodes. 1. D. Aurbach, B. D. McCloskey, L. F. Nazar, and P. G. Bruce, Nat. Energy, 1 16128 (2016).

Soft X-ray Absorption Spectroscopic Investigation of Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials.

Herein, we report the soft X-ray absorption spectroscopic investigation for Li(Ni0.8Co0.1Mn0.1)O2 cathode material during charging and discharging. These measurements were carried out at the Mn L-, Co L-, and Ni L-edges during various stages of charging and discharging. Both the Mn and Co L-edge spectroscopic measurements reflect the invariance in the oxidation states of Mn and Co ions. The Ni L-edge measurements show the modification of the oxidation state of Ni ions during the charging and discharging process. These studies show that eg states are affected dominantly in the case of Ni ions during the charging and discharging process. The O K-edge measurements reflect modulation of metal–oxygen hybridization as envisaged from the area-ratio variation of spectral features corresponding to t2g and eg states.

Benchmarking the performance of all-solid-state lithium batteries

Increasing the specific energy, energy density, specific power, energy efficiency and energy retention of electrochemical storage devices are major incentives for the development of all-solid-state batteries. However, a general evaluation of all-solid-state battery performance is often difficult to derive from published reports, mostly due to the interdependence of performance measures, but also due to the lack of a basic reference system. Here, we present all-solid-state batteries reduced to the bare minimum of compounds, containing only a lithium metal anode, β-Li3PS4 solid electrolyte and Li(Ni0.6Co0.2Mn0.2)O2 cathode active material. We use this minimalistic system to benchmark the performance of all-solid-state batteries. In a Ragone-type graph, we compare literature data for thiophosphate-, oxide-, phosphate- and polymer-based all-solid-state batteries with our minimalistic cell. Using fundamental equations for key performance parameters, we identify research targets towards high energy, high power and practical all-solid-state batteries. Considering the interdependence of performance measures and the lack of a basic reference system for all-solid-state batteries, Jurgen Janek and co-workers analyse literature performance data for major types of all-solid-state batteries and benchmark them against minimalistic reference cells.

Water-Based Process to the Preparation of Nickel-Rich Li(Ni0.8Co0.1Mn0.1)O2 Cathode

Poly(acrylic acid) (PAA) is added as a binder to the water-based slurry of Ni-rich Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) powder. After adding PAA, the pH of the slurry changes from strongly alkaline to nearly neutral (pH9.0), making it suitable for casting on the aluminum current collector without corroding the aluminum (Al) and a largely increased adhesion from 318 to 458 kg m−2 after drying. The use of PAA also improves the dispersion of the slurry, because the carboxyl groups of PAA can interact with NCM811 to help stabilize the electrode particles in the slurry. Given the improved dispersion, reduced corrosion potential, and better adhesion, the resultant NCM811 cathode exhibits good structural integrity and greatly lowered charge-transfer resistance from 37.0 to 8.5 Ω, showing a high initial capacity of 189.2 mAh g−1 and capacity retention of 84.2% after 100 charge-discharge cycles under 0.2C.

An Improved Unscented Particle Filter Method for Remaining Useful Life Prognostic of Lithium-ion Batteries With Li(NiMnCo)O2 Cathode With Capacity Diving

An improved method for the remaining useful life (RUL) prognostic of Lithium-ion batteries with Li(NiMnCo)O 2 cathode using improved unscented particle filter (UPF) is proposed with respect to capacity diving in later capacity degradation curve. Key points of this paper are: (1) An appropriate empirical model for the situation as the most contributive work, is put forward as an alternative to the widely used UPF models, and the prediction performance is respectively verified by least square fitting and the improved UPF; (2) Systematic noise in Gamma distribution is attempted in state space equations of the proposed method, so as to avoid potential shape shifting of the prediction curve after sampling the particles with Gaussian noise, for model parameters could get zero-crossed; (3) With training data preprocessed considering the capacity recovery phenomenon concisely, the residual error and root mean square error of fitting could get further reduced, as a supplement to traditional treatments like smoothing, thus relieving the sensitivity of data-driven methods to data by enhancing quality. Validations are implemented by applying the proposed method to the battery data by conducting cycle aging tests under different working conditions, where improved approximation and prediction performance can be obtained.

Porosity‐ and Graphitization‐Controlled Fabrication of Nanoporous Silicon@Carbon for Lithium Storage and Its Conjugation with MXene for Lithium‐Metal Anode

AbstractSilicon (Si) and lithium metal are the most favorable anodes for high‐energy‐density lithium‐based batteries. However, large volume expansion and low electrical conductivity restrict commercialization of Si anodes, while dendrite formation prohibits the applications of lithium‐metal anodes. Here, uniform nanoporous Si@carbon (NPSi@C) from commercial alloy and CO2 is fabricated and tested as a stable anode for lithium‐ion batteries (LIBs). The porosity of Si as well as graphitization degree and thickness of the carbon layer can be controlled by adjusting reaction conditions. The rationally designed porosity and carbon layer of NPSi@C can improve electronic conductivity and buffer volume change of Si without destroying the carbon layer or disrupting the solid electrolyte interface layer. The optimized NPSi@C anode shows a stable cyclability with 0.00685% capacity decay per cycle at 5 A g−1 over 2000 cycles for LIBs. The energy storage mechanism is explored by quantitative kinetics analysis and proven to be a capacitance‐battery dual model. Moreover, a novel 2D/3D structure is designed by combining MXene and NPSi@C. As lithiophilic nucleation seeds, NPSi@C can induce uniform Li deposition with buffered volume expansion, which is proven by exploring Li‐metal deposition morphology on Cu foil and MXene@NPSi@C. The practical potential application of NPSi@C and MXene@NPSi@C is evaluated by full cell tests with a Li(Ni0.8Co0.1Mn0.1)O2 cathode.

Li(Ni1/3Co1/3Mn1/3)O2 cathode investigated using X-ray absorption spectroscopy and transmission X-ray microscopy

In this paper, we discussed about the electrochemical behavior of the Li(Ni1/3Co1/3Mn1/3)O2 battery using X-ray absorption spectroscopy and transmission X-ray microscopy techniques. Ni ions in the cathode material undergoes change of oxidation in charging and discharging state, however, metal ions like Co and Mn do not exhibit this phenomenon. Simulation of Ni K-edge XAS spectra reflect change of coordination environment during charging and discharging. The experimental result from TXM imaging visualized the chemical distribution map for charging and discharging states at Ni K-edge.