Cathode Materials For Lithium-ion Batteries Research Articles

Enhanced mechanical and surface chemical stability in cobalt-free, high-nickel cathode materials for lithium-ion batteries

Cobalt-free, high-nickel cathode materials are essential for the sustainable evolution of energy storage technologies, reducing the dependence on resources with significant environmental and social implications and simultaneously improving the efficiency and cost effectiveness of batteries. This paper introduces a cobalt-free, high-nickel cathode material called 0.01B-LiNi0.98Mg0.01Zr0.01O2 (NMZB) developed using a novel blend of elements to enhance mechanical and surface chemical stability. Detailed evaluations confirmed the successful integration of Mg, Zr, and B into the particles, with Mg and Zr primarily located within the particle interior and B predominantly on the surface. This unique elemental configuration significantly improves the stability of the bulk phase and surface structure of the material. In addition, the refinement of primary particles within NMZB further enhances its mechanical stability. As a result, NMZB exhibits exceptional electrochemical stability, achieving 90.5 % capacity retention after 200 cycles at a 1C rate. This compositional strategy incorporates a high nickel content into layered materials while eliminating cobalt, which is crucial for advancing the development of cost effective and high-performance lithium-ion battery technology.

Assumption on the optimization direction of positive electrode materials and new methods for recycling electrode materials in lithium-ion batteries

Abstract With the increasing scarcity of non-recyclable resources such as international fossil energy and coal industries, representatives from various countries at the Paris Summit advocated the strategy of “carbon neutrality, carbon peaking” and promoted the use of recyclable resources, namely electricity. There are many ways to generate electricity, such as solar power, hydroelectric power, thermal power, tidal power and wind power. However, the method of mobile storage of electricity is relatively single - using batteries. The most widely used mobile battery currently is lithium-ion battery. This research will focus on the different choices of cathode materials for lithium-ion batteries, analysing and comparing their performance, functional stability, lifespan, capacity, price, and working conditions under extreme temperatures. At the same time, in-depth analysis will be conducted on existing electrode material recycling methods. Finally, the development direction of electrode materials with economic benefits and promising development prospects, as well as recycling methods that are more in line with economic benefits and increase resource utilization, are proposed.

Electronic structure and delithiation mechanism of vanadium and nickel doped Li2MnPO4F cathode material for lithium-ion batteries

This study calculates the energy band structure and density of states of Lithium manganese fluorophosphate (Li2MnPO4F, a lithium transition metal phosphate compounds) using the first-principles plane-wave pseudopotential approach within the density-functional theory. The model of Li2M0.5Mn0.5PO4F (M = V, Ni) with transition metal doped Mn sites is constructed by using the CASTEP module. The calculation findings indicate that the transition metal doping can regulate the energy band structure of the intrinsic system, and Li2MnPO4F makes the band gap decrease, and the volume increase with the Li ions of being deintercalated, and the electrons can be readily stimulated from the valence band to the conduction band. The findings indicate that Li2MnPO4F is a favorable cathode material for high-voltage lithium ion batteries (LIBs). The introduction of vanadium (V) and nickel (Ni) doping reduces the band gap, facilitating an easier excitation of electrons from the valence band to the conduction band. This study provides a theoretical study of new cathode materials for high performance LIBs.

Application of cathode materials in lithium ion phosphate battery and its modification

Abstract Lithium ion batteries have been widely used in various fields, such as electric vehicles, due to their excellent electrochemical performance. Especially, introducing some functional materials into batteries can further improve battery performance. This research analyses the application of lithium-ion phosphate as the cathode materials of the batteries, with a particular focus on the structural characteristics and various indices of the modification of lithium iron phosphate battery cathode materials. The electrode material is systematically described, highlighting its advantages, disadvantages, and application range while emphasizing its crucial role in different electrochemical performance such as energy density and recyclability. In addition, the relationship between the electrochemical performance and structure properties of cathode materials in LiFePO4 is summarized by placing emphasis on nanoparticle characteristics, interface environment effects, and electrode structures. This research also presents a series of achievements in modifying lithium iron phosphate cathode materials. And it identifies areas that require improvement and looks forward to future challenges and developments in lithium-ion battery cathode materials.

Nanostructured LiNi0.8Co0.1Mn0.1O2 with a Hollow Morphology Boosting Cycling Stability as Cathode Materials for Lithium-Ion Batteries

Nanostructured LiNi_0.8Co_0.1Mn_0.1O₂ with a Hollow Morphology Boosting Cycling Stability as Cathode Materials for Lithium-Ion Batteries

Ferrocene-Based Polymer Organic Cathode for Extreme Fast Charging Lithium-Ion Batteries with Ultralong Lifespans.

To meet the growing demand for energy storage, lithium-ion batteries (LIBs) with fast charging capabilities has emerged as a critical technology. The electrode materials affect the rate performance significantly. Organic electrodes with structural flexibility support fast lithium-ion transport and are considered promising candidates for fast-charging LIBs. However, it is a challenge to create organic electrodes that can cycle steadily and reach high energy density in a few minutes. To solve this issue, accelerating the transport of electrons and lithium ions in the electrode is the key. Here, it is demonstrated that a ferrocene-based polymer electrode (Fc-SO3Li) can be used as a fast-charging organic electrode for LIBs. Thanks to its molecular architecture, LIBs with Fc-SO3Li show exceptional cycling stability (99.99% capacity retention after 10 000 cycles) and reach an energy density of 183Wh kg-1 in 72 seconds. Moreover, the composite material through insitu polymerization with Fc-SO3Li and 50 wt % carbon nanotube (denoted as Fc-SO3Li-CNT50) achieved optimized electron and ion transport pathways. After 10000 cycles at a high current density of 50C, it delivered a high energy density of 304Wh kg-1. This study provides valuable insights into designing cathode materials for LIBs that combine high power and ultralong cycle life.

Synthesis and Electrochemical Performance of Na and F Elements Co-Doped LiFePO4/C as a Cathode Material for High-Rate Lithium-Ion Batteries and the Mechanism of Modification

Synthesis and Electrochemical Performance of Na and F Elements Co-Doped LiFePO4/C as a Cathode Material for High-Rate Lithium-Ion Batteries and the Mechanism of Modification

Synthesis Pathway of Layered-Oxide Cathode Materials for Lithium-Ion Batteries by Spray Pyrolysis.

We report the synthesis of LiCoO2 (LCO) cathode materials for lithium-ion batteries via aerosol spray pyrolysis, focusing on the effect of synthesis temperatures from 600 to 1000 °C on the materials' structural and morphological features. Utilizing both nitrate and acetate metal precursors, we conducted a comprehensive analysis of material properties through X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Our findings reveal enhanced crystallinity and significant oxide decomposition within the examined temperature range. Morphologically, nitrate-derived particles exhibited hollow, spherical shapes, whereas acetate-derived particles were irregular. Guided by high-temperature X-ray diffraction (HT-XRD) data, the formation of a layered LCO oxide structure, with distinct spinel Li2Co2O4 and layered oxide LCO phases was shown to emerge at different annealing temperatures. Optimally annealed particles showcased well-defined layered structures, translating to high electrochemical performance. Specifically, nitrate-based particles annealed at 775 °C for 1 h demonstrated initial discharge capacities close to 179 mAh/g, while acetate-based particles, annealed at 750 °C for 3 h, achieved 136 mAh/g at a 0.1C discharge rate. This study elucidates the influence of synthesis conditions on LCO cathode material properties, offering insights that advance high throughput processes for lithium-ion battery materials synthesis.

Cut-off voltage influencing the voltage decay of single crystal lithium-rich manganese-based cathode materials in lithium-ion batteries

The voltage decay of Li-rich layered oxide cathode materials results in the deterioration of cycling performance and continuous energy loss, which seriously hinders their application in the high-energy–density lithium-ion battery (LIB) market. However, the origin of the voltage decay mechanism remains controversial due to the complex influences of transition metal (TM) migration, oxygen release, indistinguishable surface/bulk reactions and the easy intra/inter-crystalline cracking during cycling. We investigated the direct cause of voltage decay in micrometer-scale single-crystal Li1.2Mn0.54Ni0.13Co0.13O2 (SC-LNCM) cathode materials by regulating the cut-off voltage. The redox of TM and O2− ions can be precisely controlled by setting different voltage windows, while the cracking can be restrained, and surface/bulk structural evaluation can be monitored because of the large single crystal size. The results show that the voltage decay of SC-LNCM is related to the combined effect of cation rearrangement and oxygen release. Maintaining the discharge cutoff voltage at 3 V or the charging cutoff voltage at 4.5 V effectively mitigates the voltage decay, which provides a solution for suppressing the voltage decay of Li-rich and Mn-based layered oxide cathode materials. Our work provides significant insights into the origin of the voltage decay mechanism and an easily achievable strategy to restrain the voltage decay for Li-rich and Mn-based cathode materials.

Enhancing the stability of Li-Rich Mn-based oxide cathodes through surface high-entropy strategy

Li-rich Mn-based layered oxides (LMR) hold promise as cathode materials for lithium-ion batteries (LIBs) due to their high reversible capacity. However, issues such as oxygen release and structural degradation associated with oxygen redox cause voltage decay and capacity decline during cycling. In this study, a monodisperse Li1.2Ni0.13Co0.13Mn0.54O2 cathode material with surface high-entropy architecture (MZCN-LMR) was synthesized to enhance the overlap between the non-bonding orbitals of oxygen (|O2p) and the (TM-O)* occupied band. This enhancement enables regulation of the depth of oxygen oxidation, improving reversible oxygen redox and creating highly flexible structures, with mitigated anisotropic modulus and lattice strain evolution during (de)intercalation. Consequently, the developed MZCN-LMR cathode exhibits impressive capacity retention of 80.5 % after 400 cycles and minimal voltage decay of 0.7 mV per cycle with the voltage range of 2.1–4.6 V. This surface high-entropy strategy offers a universal approach to enhancing the redox stability of anions, contributing to the application of LMR.

Li2ZrO3 coated LiFe0.4Mn0.6PO4/C with enhanced cycling performance at elevated temperature for lithium-ion batteries

Lithium iron manganese phosphate (LFMP) is regarded as one of the most promising cathode materials for lithium-ion batteries due to its high energy density and low cost. However, the Jahn-Teller effect of Mn3+ inevitably causes the dissolution of Mn during the cycling process, is accompanied by a severe decrease in the discharge capacity and a decline in capacity retention rate, which is more serious at elevated temperature. Here, the LiFe0.4Mn0.6PO4/C (LFMP-0LZO) cathode material is prepared via carbothermal reduction method, and its surface is modified by Li2ZrO3 (LFMP-1LZO) to enhance the surface stability and improve the cycling performance at room temperature and elevated temperature. The residual capacities of LFMP-0LZO sample is 113.7 mAh g−1, with a capacity retention rate of only 75.55 % after 150 cycles at 55 °C and a current density of 1C (1C = 170 mA g−1), while the discharge capacity of 1 wt% Li2ZrO3-coated material (LFMP-1LZO) under the same conditions is 134.85 mAh g−1, with a higher capacity retention rate of 87.49 %. Furthermore, a series of characterization experiments show that the surface modification of LiFe0.4Mn0.6PO4/C with Li2ZrO3 can effectively inhibit the side reaction between the electrode/electrolyte interface and reduce the dissolution of Mn in the active substance.

Constructing High-Performance Cobalt-Based Environmental Catalysts from Spent Lithium-Ion Batteries: Unveiling Overlooked Roles of Copper and Aluminum from Current Collectors.

Converting spent lithium-ion batteries (LIBs) cathode materials into environmental catalysts has drawn more and more attention. Herein, we fabricated a Co3O4-based catalyst from spent LiCoO2 LIBs (Co3O4-LIBs) and found that the role of Al and Cu from current collectors on its performance is nonnegligible. The density functional theory calculations confirmed that the doping of Al and/or Cu upshifts the d-band center of Co. A Fenton-like reaction based on peroxymonosulfate (PMS) activation was adopted to evaluate its activity. Interestingly, Al doping strengthened chemisorption for PMS (from -2.615 eV to -2.623 eV) and shortened Co-O bond length (from 2.540 Å to 2.344 Å) between them, whereas Cu doping reduced interfacial charge-transfer resistance (from 28.347 kΩ to 6.689 kΩ) excepting for the enhancement of the above characteristics. As expected, the degradation activity toward bisphenol A of Co3O4-LIBs (0.523 min-1) was superior to that of Co3O4 prepared from commercial CoC2O4 (0.287 min-1). Simultaneously, the reasons for improved activity were further verified by comparing activity with catalysts doped Al and/or Cu into Co3O4. This work reveals the role of elements from current collectors on the performance of functional materials from spent LIBs, which is beneficial to the sustainable utilization of spent LIBs.

Ultrathin Titanium Dioxide Coating Enables High-Rate and Long-Life Lithium Cobalt Oxide.

Lithium cobalt oxide (LCO) has been widely used as a leading cathode material for lithium-ion batteries in consumer electronics. However, unstable cathode electrolyte interphase (CEI) and undesired phase transitions during fast Li+ diffusivity always incur an inferior stability of the high-voltage LCO (HV-LCO). Here, an ultra-thin amorphous titanium dioxide (TiO2) coating layer engineered on LCO by an atomic layer deposition (ALD) strategy is demonstrated to improve the high-rate and long-cycling properties of the HV-LCO cathode. Benefitting from the uniform TiO2 protective layer, the Li+ storage properties of the modified LCO obtained after 50 ALD cycles (LCO-ALD50) are significantly improved. The results show that the average Li+ diffusion coefficient is nearly tripled with a high-rate capability of 125 mAh g-1 at 5C. An improved cycling stability with a high-capacity retention (86.7%) after 300 cycles at 1C is also achieved, far outperforming the bare LCO (37.9%). The in situ XRD and ex situ XPS results demonstrate that the dense and stable CEI induced by the surface TiO2 coating layer buffers heterogenous lithium flux insertion during cycling and prevents electrolyte, which contributes to the excellent cycling stability of LCO-ALD50. This work reveals the mechanism of surface protection by transition metal oxides coating and facilitates the development of long-life HV-LCO electrodes.

Hydrothermal synthesize of bi-functional interface structure modified LiMnPO4@LiFePO4/C nanorods as cathode materials for lithium-ion batteries

Olivine-structured LiMnPO4-based cathodes have generated enormous development prospects due to their high energy density, good structural stability, and low cost. However, their scale of application is limited by high electronic and ionic insulativity. In this study, we designed and synthesized a bi-functional interfacial modified composite, 0.9LiMnPO4@0.1LiFePO4/C (0.9LMP@0.1LFP/C), using mechanochemical activation-assisted hydrothermal technology. The innovative Li-storage structure consists of a high-energy density LiMnPO4 (LMP) core, a uniformly coated LiFePO4 (LFP) layer with improved ionic conductivity as the secondary outer shell, and an in-situ coated carbon film with high conductivity as the outermost functional skin. As anticipated, the 0.9LMP@0.1LFP/C composite exhibits outstanding Li-storage properties, demonstrating discharge capacities as high as 157.1 mAh g−1 and 146.7 mAh g−1 at 0.1 C and 1 C rates, respectively. Moreover, it exhibits an ultrahigh capacity retention of 92.5 % after 500 charge and discharge cycles.

Effects of different Ti concentrations doping on Li2MnO3 cathode material for lithium-ion batteries via density functional theory

Li2MnO3 is extensively studied for a cathode material in lithium-ion batteries because of its high voltage and specific capacity. Nevertheless, it has the disadvantages due to low conductivity and Li-ion diffusion. To modify its performance, we determine the structure stability and electronic properties of Li2MnO3 cathodes doped with different Ti-ion concentrations using the spin-polarized density functional theory including the Hubbard term (DFT + U). For the calculations, cell parameters, formation energies, band gaps, total density of states, partial density of states and stability voltages are determined. The results highlight that the expansion of the cell volumes by Ti-ion impurities has a positive effect on the diffusion of Li ions in these cathodes. Because of the minor voltage changes, Li2MnO3 cathode doped with a Ti-ion concentration of 0.250 exhibits the highest voltage stability. Overall, these results are effective for the lithium-ion battery application based on Ti-doped Li2MnO3 cathodes.

Design of double layer cathode electrode for improving the safety and stability of lithium-ion batteries

LiNi0.8Co0.1Mn0.1O2 (NCM) is a widely used cathode material for lithium-ion batteries (LIBs). However, the poor cycle performance and safety issue remains a huge challenge for its practical applications. Here we show a simple double layer strategy to improve the electrochemical characteristics and safety performance. NCM was coated by LiFePO4 (LFP), a safe cathode material with long cycle stability, exhibited more excellent cycling stability and similar rate properties at room temperature (called NCM/LFP). Under 45 ℃, the NCM/LFP (6:1)||graphite pouch cell shows excellent 83% capacity retention after 600 cycles at 1C, which compared to the sharp attenuation of pristine NCM. Furthermore, NCM/LFP (6:1)||graphite cell could pass the nail penetration tests and the thermal runaway temperature (TTR) delayed by 193℃, which proved the double layer design has better safety performance. The current work might pave an avenue for cathode materials, as a sustainable solution to high energy density LIBs for applications.

Garnet conductor network with Zr doping to implement surface bifunctional modification for Ni-rich cathodes

High‑nickel oxides are promising cathode materials for next-generation lithium batteries due to their high discharge capacity. LiNi0.83Co0.11Mn0.06O2(NCM83), a polycrystalline material widely used for its excellent performance, faces challenges such as interfacial side reactions and lattice oxygen release that hinder its electrochemical performance under high voltage. To promote the high-voltage performance of NCM83, Li7La3Zr2O12, a fast ion conductor with high conductivity and a wide electrochemical window, is taken into account. Here, the oxidation reaction and element diffusion are employed during high-temperature sintering to realize dual functional modification of NCM83 materials, including La-rich conductor network construction and near-surface Zr doping. Impressively, the modified electrode shows excellent cycling performance with 82.14 % retention after 200 cycles at 2.8–4.6 V, and splendid rate capability. Detailed studies reveal that ZrO bonds inhibit the migration of transition metal ions, preventing the distortion of the material structure. The surface ionic conductor network layer provides fast Li+ diffusion channels and protects the interfacial layer from electrolyte decomposition products. The facile Li7La3Zr2O12 modification method proposed in this paper is suitable for solving the interfacial and structural stability of cathode materials, offering hope for the application of high-energy lithium-ion batteries.

Optimal design of LiMn2O4 for high-rate applications by means of citric acid aided route and microwave heating

Due to shortening the duration of the process and possibility to obtain crystals of smaller and uniform size, microwave heating is considered an effective and promising tool for the synthesis of LiMn2O4, a valuable cathode material for lithium-ion batteries. However, electrochemical characteristics of LiMn2O4 obtained with its help are almost completely absent and do not allow for drawing a sound conclusion regarding advantages and drawbacks of microwave processing. Here we present a description of the microwave-assisted citric acid aided synthesis, characterization and electrochemical performance of LiMn2O4. The disclosure of detailed working protocols enabling one to manufacture samples tolerant to extremely high currents is the main novelty of this paper. Specifically, our material sustains current loads up to 40 C (5920 mA g-1) and completely recovers after cycling at harsh conditions.

Multiple-functional LiTi2(PO4)3 modification improving long-term performances of Li-rich Mn-based cathode material for advanced lithium-ion batteries

Li-rich layered oxides with high energy densities have become one kind of promising cathode for advanced lithium-ion batteries, however some issues are severely hindering their practical applications. To address these challenges, fast ion conductive LiTi2(PO4)3 (LTPO) is employed to modify the typical Li-rich cathode Li1·2Mn0·56Ni0·17Co0·07O2 (LMNCO) via a sol-gel process combined with a two-step annealing treatment in this work. Serving as a physical separator, LTPO coating effectively depresses the side reactions at cathode-electrolyte interface and the transition-metal dissolution from LMNCO active material under harsh electrochemical environment. Meanwhile, LTPO layer with high ion conductivity could facilitate the interfacial Li+ diffusion during charge/discharge process. In addition, partial Ti4+ ions doped into LMNCO effectively elevate the oxygen electronegativity and restrain the excessive oxidization of lattice oxygen, thus stabilizing the crystal structure and alleviating the stress-strain propagation upon cycling. Electrochemical characterization results demonstrate that the LTPO-modified LMNCO cathode exhibits a superior capacity retention of 86.5 % after 400 cycles at room temperature and that of 73.7 % even under an elevated temperature of 45 °C after 250 cycles under 1C. This study provides a facile strategy for the surface modification of Li-rich layered-structure oxides, which also sheds light in enhancing electrochemical performances for various cathode materials.

Facile synthesis of a carbon supported lithium iron phosphate nanocomposite cathode material from metal-organic framework for lithium-ion batteries

Lithium iron phosphate (LiFePO4, LFP) has become one of the most widely used cathode materials for lithium-ion batteries. The inferior lithium-ion diffusion rate of LFP crystals always incurs poor rate capability and unsatisfactory low-temperature performances. To meet with the requirements from the ever-growing market, it is of great significance to synthesize carbon supported LFP nanocomposite (LFP/C) cathode materials using cost effective and environmentally friendly methods. In this work, an LFP/C cathode material is straightforwardly prepared from a metal–organic framework (MOF) precursor ferric gallate (Fe-GA) using its self-template effect. The Fe-GA precursor is firstly fabricated from the redox coprecipitation reaction between Fe foils and gallic acid (GA) molecules in mild aqueous phase. Then the Fe-GA is directly converted to the LFP/C sample after a following solid-state reaction. In half-cells, the LFP/C composite exhibits a reversible capacity of 109.7 mAh·g−1 after 500 cycles under the current rate of 100 mA·g−1 at 25 °C as well as good rate capabilities. In the LFP/C//graphite full-cells, the LFP/C composite can deliver a reversible capacity of 71.4 mAh·g−1 after 50 cycles in the same condition as the half-cells. The electrochemical performances of the LFP/C cathode in half-cells at lower temperature of −10 °C are also examined. Particularly, the evolution of samples has been explored and the lithium-ion storage mechanism of the LFP/C cathode has been unveiled. The sample synthesis protocol is straightforward, eco-friendly and atomic efficient, which can be considered to have good potential for scaling-up.