Commercial Lithium-ion Batteries Research Articles

High Selenium Loading in Vertically Aligned Porous Carbon Framework with Visualized Fast Kinetics for Enhanced Lithium/Sodium Storage

AbstractLithium/sodium–selenium (Li/Na–Se) batteries with high volumetric specific capacity are considered promising as next‐generation battery technologies. However, their practical application is hindered by challenges such as low Se loading in cathodes and the polyselenides shuttle effect. To address these challenges, a new Se host is introduced in the form of a free‐standing N, O co‐doped vertically aligned porous carbon framework decorated with a carbon nanotube forest (VCF‐CNTs), allowing for high mass loading of up to 16 mg cm−2. The low‐tortuosity Se@VCF‐CNTs architecture facilitates rapid lithiation/sodiation kinetics, while the CNT forests in vertical microchannels enhance efficient Se loading and serve as a multi‐layer fence to prevent undesired polyselenide shuttling. Consequently, the Se@VCF‐CNTs cathode displays a significant areal capacity of 10.3 mAh cm−2 at 0.1 C with a Se loading of 16 mg cm−2 for Li–Se batteries, exceeding that of commercial lithium ion batteries (4.0 mAh cm−2). In Na–Se batteries, the Se@VCF‐CNTs electrode with a Se loading of 5 mg cm−2 exhibits a discharge capacity of 436 mAh g−1 after 200 cycles, proving its consistent cycling performance. This study enriches the field of knowledge concerning high‐loading Se‐based battery systems, offering a promising avenue for enhancing energy density in the field.

Crucial Roles of Ethyl Methyl Carbonate in Lithium-Ion and Dual-Ion Batteries: A Review.

The essential role of electrolyte solutions in traditional electrochemical energy storage devices is crucial to enhancing their performance. Consequently, a wide array of electrolyte mixtures along with diverse electrodes have been extensively explored across different models of secondary batteries. Fascinatingly, the role of ethyl methyl carbonate (EMC) as a key cosolvent in the electrolyte mixture of commercial lithium-ion batteries with a graphite anode is garnering growing attention in alternative rechargeable dual-ion batteries utilizing graphite cathodes. In this context, the advancement and function of EMC as a solvent in electrolyte mixtures for lithium-ion and dual-ion batteries were extensively and thoroughly examined in this analysis, encompassing the genesis, synthesis process, and diverse characteristics for the practical uses of these batteries. Here, the review aims to guide readers in understanding EMC's function and impact as a cosolvent in electrolyte mixtures for both major secondary lithium-ion and dual-ion batteries, considering their distinct physicochemical characteristics.

High‐Safety Anode Materials for Advanced Lithium‐Ion Batteries

Lithium‐ion batteries (LIBs) play a pivotal role in today's society, with widespread applications in portable electronics, electric vehicles, and smart grids. Commercial LIBs predominantly utilize graphite anodes due to their high energy density and cost‐effectiveness. Graphite anodes face challenges, however, in extreme safety‐demanding situations, such as airplanes and passenger ships. The lithiation of graphite can potentially form lithium dendrites at low temperatures, causing short circuits. Additionally, the dissolution of the solid‐electrolyte‐interphase on graphite surfaces at high temperatures can lead to intense reactions with the electrolyte, initiating thermal runaway. This review introduces two promising high‐safety anode materials, Li4Ti5O12 and TiNb2O7. Both materials exhibit low tendencies towards lithium dendrite formation and have high onset temperatures for reactions with the electrolyte, resulting in reduced heat generation and significantly lower probabilities of thermal runaway. Li4Ti5O12 and TiNb2O7 offer enhanced safety characteristics compared to graphite, making them suitable for applications with stringent safety requirements. This review provides a comprehensive overview of Li4Ti5O12 and TiNb2O7, focusing on their material properties and practical applicability. It aims to contribute to the understanding and development of high‐safety anode materials for advanced LIBs, addressing the challenges and opportunities associated with their implementation in real‐world applications.

Synthesis of high-voltage spinel LiNi0.5Mn1.5O4 by Mn2O3 nanosheets for lithium-ion batteries with superior cycle life span

The development of high-voltage cobalt-free spinel LiNi0.5Mn1.5O4 (LNMO) by conventional solid-state methods is hampered by its rapid capacity decay due to the impurity phases, inhomogeneous particle size, and dissolution of transition metals. To realize large-scale production and application of LNMO, a two-step modified solid-state method with Mn2O3 nanosheets as a precursor is proposed here. The resulting material (P-LNMO) shows a reduced rock salt impurity phase and enhanced ionic transport through a more uniform control of particle size. As a result, the cycling stability of the disordered LNMO is remarkably improved, where LNMO half-cell capacity retention is 89.5 % at ambient temperature after 1000 cycles. What's more, the LNMO/Graphite full-cell is further assembled showing a discharge specific capacity of 110 mAh g−1 at 1C, and remains 97 % of its initial capacity after 100 cycles. The excellent electrochemical performance indicates that this modified solid-state approach brings a new avenue to the synthesis of LNMO for the upcoming generation of commercial lithium-ion batteries.

Unraveling the relationship between the mineralogical characteristics and lithium storage performance of natural graphite anode materials

Anode materials play critical role in cycling life of lithium-ion batteries in practical applications such as electric vehicles (EVs), portable electronic devices, and large-scale power grids. Natural graphite is one of the most successful anodes for commercial lithium-ion batteries due to its high theoretical capacity and low cost and low operating voltage. The mineralogical properties of graphite minerals have an important effect on the electrochemical performance of graphite anode, while their relationship remains ambiguous. In this work, natural graphite samples from four main graphite mining areas in China were selected as the research object, and their mineralogical characteristics were characterized by XRD, SEM, Raman, ICP, SEM, FIB, BET and other test methods. The properties of crystallinity, morphology, surface/phase defects, impurities, and specific surface area of graphite were studied. The results show that the cyclic stability of graphite is mainly affected by bulk defects and crystallinity, and the initial coulombic efficiency is mainly affected by surface defects and specific surface area. Graphite samples with appropriate surface defects, fewer volume defects, appropriate crystallinity, and small specific surface area have better electrochemical performance. It is hoped that this work should guide the manufacture and modification of the natural graphite anodes and promote its wider application in lithium-ion batteries.

Recent Advances of Metal Fluoride Compounds Cathode Materials for Lithium Ion Batteries: A Review

Abstract As the most successful new energy storage device developed in recent decades, lithium-ion batteries (LIBs) are ubiquitous in the modern society. However, current commercial LIBs comprising mainly intercalated cathode materials are limited by the theoretical energy density which cannot meet the high storing energy demanded by renewable applications. Compared to intercalation-type cathode materials, low-cost conversion-type cathode materials with a high theoretical specific capacity are expected to boost the overall energy of LIBs. Among the different conversion cathode materials, metal fluorides have become a popular research subject for their environmental friendliness, low toxicity, wide voltage range, and high theoretical specific capacity. In this review, we compare the energy storage performance of intercalation and conversion cathode materials based on thermodynamic calculation and summarize the main challenges. The common conversion-type cathode materials are described and their respective reaction mechanisms are discussed. In particular, the structural flaws and corresponding solutions and strategies are described. Finally, we discussed the prospective of metal fluorides and other conversion cathode materials to guide further research in this important field.

Aging Mechanisms and Evolution Patterns of Commercial LiFePO4 Lithium-Ion Batteries

Aging Mechanisms and Evolution Patterns of Commercial LiFePO4 Lithium-Ion Batteries

One-pot synthesis of interconnected carbon-coated silicon nanosheets from clay minerals for high-performance lithium-ion battery anodes

The silicon nanosheet/carbon composite emerges as a promising anode material for the next-generation commercial lithium-ion batteries. However, complex, costly, and energy-intensive synthesis procedures impede its practical application. Herein, the carbon-coated silicon nanosheets (Si/C) have been successfully synthesized via a one-pot strategy, involving a modified magnesiothermic reduction of talc followed by a reaction with CO2. The distinct chemical composition and layered nanostructure of talc enable the retention of Si nanosheets during exothermic reactions without additional templates or heat absorbents. The method shows significant potential for the scalable production of Si/C owing to the abundant silicon source, sustainable carbon source, and straightforward protocol. The resulting Si/C displays a hierarchical porous structure, with both macropores and mesopores, and an interconnected network of carbon-coated Si nanosheets. These structural characteristics facilitate rapid Li+ diffusion and enable the material to accommodate the lithiation-induced mechanical strains. As a result, the Si/C electrode exhibits outstanding electrochemical performance, including a remarkable rate capability (with a specific capacity of 1220 mAh g−1 at 10.0 A g−1) and a high initial Coulombic efficiency of 88%. The work opens a new avenue for the development of Si/C composites from natural clay minerals through an economical and scalable strategy, which would contribute to the practical application of advanced Si-based anodes in lithium-ion batteries.

Highly Conductive Carbon/Carbon Composites as Advanced Multifunctional Anode Materials for Structural Lithium‐Ion Batteries

AbstractCurrently, structural lithium‐ion batteries (LIBs) typically use carbon fibers (CFs) as multifunctional anode materials to provide both Li+ storage and high mechanical strength. However, due to the obvious volume expansion of CFs in lithiation process, the fiber structure suffers rapid degradation during cycling. Herein, CFs‐reinforced carbon matrix (C/C) composites are proposed as multifunctional anodes for structural LIBs for the first time. The C/C composite presents distinctive core/shell structure, in which CF as the core supplies a fast and continuous electron conduction pathway along with excellent mechanical strength, while the layered pyrolytic carbon shell accommodates the volume change of CF and provides additional ion storage. The impact of the C/C microstructure on the ion/electron transport and the Li+ storage mechanism behind such a unique hybrid structure are explored. Owing to the structural advantages of the C/C composite, the LiFePO4||C/C full cell exhibits surprising electrochemical performances at high electrode mass loadings, which are far superior to those of the present structural LIBs and even surpass the commercial LIBs at the same mass loadings. Moreover, the pouch cell presents excellent mechanical strength and mechanical‐electrochemical coupling characteristics. This work demonstrates great potential of the C/C composites as new multifunctional anodes for high‐performance structural batteries.

The gas production characteristics and catastrophic hazards evaluation of thermal runaway for LiNi0.5Co0.2Mn0.3O2 lithium-ion batteries under different SOCs

Lithium-ion batteries (LIBs) are widely used as electrochemical energy storage systems in electric vehicles due to their high energy density and long cycle life. However, fire accidents present a trend of frequent occurrence caused by thermal runaway (TR) of LIBs, so it is especially important to evaluate the catastrophic hazards of these LIBs. This study conducted the adiabatic TR test coupled gas production test, Gas Chromatography-Mass Spectrometry test, and explosion limit test on a commercial LIB with Ni0.5Co0.2Mn0.3 as the cathode material at different states of charge (SOCs). The results show that the TR temperature and the maximum temperature at low SOC are lower compared to that at a high SOC. The probability of LIBs TR at less than SOC = 50 % is small and also causing less harm. For the gas production characteristics, the lower the SOC of the battery, the lower the gas production volume. The peak and steady-state gas production increase with the increase of SOC. For the mixed gases generated during TR, the content of CO2 shows a trend of decreasing with the increasing of battery SOC, while that of H2 and CO increase with the increasing of SOC. For the explosion limit of the mixed gas, the lower explosion limit and upper explosion limit decrease and increase with the increasing of SOC, respectively. Finally, based on the seven parameters related to the TR gas production of LIBs and so on, the analytic hierarchy process method was used to establish a LIB TR disaster-causing hazard evaluation system. The evaluation system can quantitatively evaluate the thermal safety of a LIB. This is instructive for establishing a comprehensive quantitative evaluation method for battery safety in practical engineering applications.

Unraveling capacity recovery behavior of 78 Ah pouch cells after long-term storage for EVs: Passive anode and calendar-aged SEI effects

The unavoidable long-term storage after production can result in capacity and power fading in commercial lithium-ion batteries. Remarkably, the decreased capacity is partially and gradually recovered when the stored cells are cycled again, known as capacity recovery. However, it is challenging to analyze the capacity recovery phenomenon independently from the capacity decay during re-cycling. Moreover, the most well-known explanation for capacity recovery, the passive anode effect (PAE) is only focus on the lithium inventory inside the overhang anode site. To address these issues, the large-capacity LiNi0.4Co0.3Mn0.3O2/graphite pouch cells stored for 4 years is used. Typically, throughout the re-cycling, the capacity is gradually recovered up to 120 cycles, and the fully recovered capacity was maintained up to 500 cycles, indicating that additional capacity decay by re-cycling was almost suppressed. Also, we clearly reveal the impact of breakdown and thinning of the calendar-aged solid electrolyte interphase (SEI) on the whole anode site influences both capacity and power recovery, not just limited to the PAE. Furthermore, by combining both the PAE and breakdown of the calendar-aged SEI into a life prediction model, the capacity recovery behavior for up to 1000 cycles under various operating conditions can be predicted.

Diphenylphosphoryl Azide as a Multifunctional Flame Retardant Electrolyte Additive for Lithium-Ion Batteries

Graphite anode materials and carbonate electrolyte have been the top choices for commercial lithium-ion batteries (LIBS) for a long time. However, the uneven deposition and stripping of lithium cause irreversible damage to the graphite structure, and the low flash point and high flammability of the carbonate electrolyte pose a significant fire safety risk. Here, we proposed a multifunctional electrolyte additive diphenylphosphoryl azide (DPPA), which can construct a solid electrolyte interphase (SEI) with high ionic conductivity lithium nitride (Li3N) to ensure efficient transport of Li+. This not only protects the artificial graphite (AG) electrode but also inhibits lithium dendrites to achieve excellent electrochemical performance. Meanwhile, the LIBS with DPPA offers satisfactory flame retardancy performance. The AG//Li half cells with DPPA-0.5M can still maintain a specific capacity of about 350 mAh/g after 200 cycles at 0.2 C. Its cycle performance and rate performance were better than commercial electrolyte (EC/DMC). After cycling, the microstructure surface of the AG electrode was complete and flat, and the surface of the lithium metal electrode had fewer lithium dendrites. Importantly, we found that the pouch cell with DPPA-0.5M had low peak heat release rate. When exposed to external conditions of continuous heating, DPPA significantly improved the fire safety of the LIBS. The research of DPPA in lithium electrolyte is a step towards the development of safe and efficient lithium batteries.

Ladderlike polysilsesquioxanes derived dual-carbon-buffer-shell structural silicon as stable anode materials for lithium-ion batteries

Silicon-carbon (Si/C) composite materials have been proven to be one of the most promising anode materials for the next generation of lithium-ion batteries (LIBs) due to their high theoretical capacity. However, the substantial volume changes during alloying/dealloying processes have posed significant challenges to the working lifespan of Si-based anodes. In this study, we designed a dual-carbon-layer-structured Si composite anode material (DCS-Si). Using ladderlike polysilsesquioxanes as a precursor, we employed a zinc thermal reaction to internally reduce the Si–O–Si framework to Si0. Simultaneously, the phenyl groups directly connected to Si atoms served as a carbon source for the internally dense coating layer. The obtained product underwent further coating controllable pyrolysis reactions to form an external carbon coating layer. As anode for LIBs, DCS-Si delivered a reversible specific capacity exceeding 1000 mAh g−1. Even after 1350 cycles at a current density of 0.3 A g−1, the specific capacity remained above 500 mAh g−1. Moreover, even under a high current density of 3 A g−1, after nearly 1000 cycles, the capacity retention rate still exceeded 70%. Further testing of the full cell also indicated that DCS-Si is a highly promising high-energy-density anode, with potential applications in future commercial lithium-ion batteries.

Pentafluorophenyl diethoxy phosphate: An electrolyte additive for high-voltage cathodes of lithium-ion batteries

Increasing the upper limit of the charging voltage in commercial lithium-ion batteries (LIBs) can enable them to have a higher energy density, but during high-voltage charging and discharging, the electrolyte will accelerate the decomposition, and the interfacial adverse reaction among the cathode and electrolyte is serious, which corrodes the cathode active material and consumes excessive electrolyte, and ultimately lead to a shorter service life of lithium-ion batteries. To address this issue, an electrolyte additive with properties suitable for high voltage cathodes, named pentafluorophenyl diethoxy phosphate (FPOP), was synthesized in this work and successfully applied to LiNi0.8Co0.1Mn0.1O2 cathode (NCM-811). Density Functional Theory (DFT) computations reveal that the FPOP additive undergoes preferential oxidation and self-polymerizes on the NCM-811 cathode surface to establishing a safeguarding film at the cathode-electrolyte interface (CEI). This film effectively inhibits detrimental side reactions. The electrochemical performance test data indicated that the retention rate of discharge-specific capacity in batteries was markedly enhanced with 0.1 wt% of FPOP when added to the standard electrolyte. Specifically, after subjecting the batteries to 200 cycles at a current of 0.2C and under voltages ranging from 4.2 V to 4.5 V, the retention of discharge ratio capacity increased by 37.6 %, 39.2 %, 26.9 %, and 37.1 % correspondingly. Morphology characterization and spectroscopic characterization showed that FPOP could not only construct a stable CEI film by oxidation during the first stages of lithium precipitation but also remove HF by strongly binding to the HF in the electrolyte or dissociating H+ and F− from HF, which ultimately enhanced the batteries' capacity to operate effectively at elevated voltage levels. Therefore, incorporating FPOP as an additive in electrolyte presents a cost-efficient approach to achieving elevated energy density.

Towards Long-Term Monitoring of Commercial Lithium-Ion Batteries Enabled by Externally Affixed Fiber Sensors and Strain-Based Prognostic Strategies

Abstract Real-time monitoring of both continuous and spontaneous degradation in lithium-ion batteries is challenging due to the limited number of quantitative metrics available during cycling. In this regard, improved sensing approaches enabled by sensors of high accuracy, precision, and durability are key to achieving comprehensive state estimation and meeting rigorous safety standards. In this work, external temperature and strain monitoring in commercial Li-ion button cells was carried out using tandem pairs of polymer-based and silica-based optical fiber Bragg grating sensors. The decoupled data revealed that the sensors can reliably track strain and temperature evolution for over 500 cycles, as evidenced by periodic patterns with no sign of sensor degradation or loss of fidelity. Moreover, monitoring the strain signal enabled early detection of an anomalous cell over ~60 cycles ahead of an electrochemical signature and abrupt drop in capacity, suggesting that mechanical sensing data may offer unique benefits in some cases. Detailed mechanical monitoring via incremental strain analysis suggests a parallel path toward understanding cell degradation mechanisms, regardless of whether they are continuous or discrete in nature. The accuracy and durability of such a package-level optical fiber sensing platform offer a promising pathway for developing robust real-time battery health monitoring techniques and prognostic strategies

Discharge and Thermal Distribution Characteristics of Electric Vehicle Battery Pack in Closed Circuit System

This paper presents an experimental study of the depth of discharge (DOD) and temperature distribution characteristics at different locations of the lithium-ion battery (LIB) pack in the closed circuit system. Three different discharge power setups i.e., 600 W, 800 W, and 1000 W are prepared for investigating the depth of discharge and temperature characteristics of commercial LIB. Voltage measurement was implemented to achieve the DOD curve, while thermocouple measurement was used to identify real-time temperature at four different locations of the LIB. As a result, internal resistance and discharging time tend to be increased, while the voltage and current decline linearly from 0% to 80% of LIB capacity. Discharge power greatly affected the four variables when the process continued to the 10% cut-off voltage. Furthermore, the heat generation of the LIB caused a rise in temperature on its surface. The highest temperature was identified on the LIB cell surface followed by an air gap, internal surface casing, and external surface casing temperature. Among all locations, the real-time temperature on the LIB surface operated close to the upper limit of optimum temperature. Due to that reason, increasing of discharge power should be maintained to extend battery cycle life as well as to prevent battery failure. The high-temperature difference between the LIB surface and air gap during the discharging process indicated that there is required heat transfer enhancement.

Ultrafast synthesis of spinel AMn2O4 (A= Co, Mn, Zn) nanopolyhedras and their composites applied to lithium ion battery anode

Spinel oxide anode materials are hardly used for commercial lithium-ion batteries because of their evident volume expansion in the discharging process and poor electronic conduction. Preparing a composite material of nanostructured spinel bimetallic oxides and carbon will solve the above problems and achieve outstanding electrochemical performance. In this study, an ultrafast approach (only 10 min) to synthesize spinel AMn2O4 (A= Co, Mn, Zn) nanopolyhedras and their composites with GO was successfully developed. Integrating spinel CoMn2O4 nanopolyhedras with GO can profoundly inhibit the problem of volume expansion but also eminently upgrading conductivity. The CoMn2O4/GO composite anode displays competent cyclic life and rate capability for lithium ion battery, delivering a large capacity of 738 mAh g−1 after 340 cycles at 2 A g−1. The ultrafast approach and alluring electrochemical performance of this work will inevitably give impetus to the fast development and application of spinel oxides.

Effect of Aging Path on Degradation Characteristics of Lithium-Ion Batteries in Low-Temperature Environments

Typical usage scenarios for energy storage and electric vehicles (EVs) require lithium-ion batteries (LIBs) to operate under extreme conditions, including varying temperatures, high charge/discharge rates, and various depths of charge and discharge, while also fulfilling vehicle-to-grid (V2G) interaction requirements. This study empirically investigates the impact of ambient temperature, charge/discharge rate, and charge/discharge cut-off voltage on the capacity degradation rate and internal resistance growth of 18,650 commercial LIBs. The charge/discharge rate was found to have the most significant influence on these parameters, particularly the charging rate. These insights contribute to a better understanding of the risks associated with low-temperature aging and can aid in the prevention or mitigation of safety incidents.

Influence of cathode materials on thermal characteristics of lithium-ion batteries.

In this work, the thermal stability of four types of 18,650 lithium-ion batteries with LiCoO2 (LCO), LiFePO4 (LFP), LiNi0.8Co0.1Mn0.1O2 (NCM811) and LiNi0.8Co0.15Al0.05O2 (NCA) materials as cathodes are experimentally investigated by the accelerating rate calorimeter (ARC) and the isothermal battery testing calorimeter (iso-BTC) under adiabatic and isothermal conditions, respectively. The thermal runaway danger level of these batteries can be ranked as LCO > NCA > NCM811 >> LFP by judging from the values of Tmax and HRmax, nominal. The higher the nickel and cobalt content, the higher the lithium-ion battery capacity, but the worse the thermal stability. The Qtotal of NCA is the largest in the complete standard charge and discharge process, due to that the capacity of NCA is significantly higher than that of the other three batteries, resulting in remarkable increase in Qirre proportioned to the square of the current. When the ambient temperature rises, the energy release decreases owing to the decrease in the internal resistance of the battery. These studies are expected to have important implications for the subsequent safe design of commercial lithium-ion batteries with different cathode materials.

A self-attention knowledge domain adaptation network for commercial lithium-ion batteries state-of-health estimation under shallow cycles

Accurate state-of-health (SOH) estimation is crucial for the safety, efficiency, and reliability of battery-powered systems. Conventional SOH estimation methods are designed for the full state-of-charge (SOC) range of 0%–100%, assuming uniform distributions. Yet, batteries in real-world applications often operate under partial SOC ranges and experience shallow-cycle conditions, which result in distinct and unlabeled degradation profiles that make SOH estimation more complex. To tackle this issue, we propose a novel method—self-attention knowledge domain adaptation network (SKDAN)—which utilizes a self-attention distillation module combined with a multi-kernel maximum mean discrepancy framework to effectively navigate between these disparate domains. This strategy successfully extracts domain-specific features from charging curves, facilitating the transfer of knowledge from well-labeled full cycles to unlabeled shallow cycles. The effectiveness of the SKDAN method is validated through extensive testing on the CALCE and SNL battery datasets, demonstrating its robust capability to estimate SOH accurately across different SOC ranges, temperatures, and discharge rates. With a root-mean-square error (RMSE) of less than 2%, the SKDAN method outperforms existing transfer learning techniques for various SOC ranges. Additionally, it exhibits exceptional SOH estimation performance when applied to batteries from different manufacturers and operating under varied conditions. This study represents the first instance of accurately estimating battery SOH under shallow-cycle conditions without relying on full-cycle characteristic tests.