During charge and discharge of lithium-ion battery, the concentration gradient produced by lithium- ion diffusion process and deformation caused by lithiation expansion of the active material result in diffusion-induced stress. Excessive diffusion-induced stress can cause various mechanical failure modes such as cracking of active particles, separation between active particles, fracture of active layers, and delamination between active layers and current collectors, which eventually leads to a series of failure phenomena such as capacity attenuation, impedance rise and cycle life loss of the battery. Therefore, the diffusion-induced stress and the derived failure mechanism of lithium-ion battery become one of the research hotspots in the field of lithium-ion batteries, which has important theoretical and practical value. In this paper, research progress of the failure mechanism of lithium-ion battery caused by diffusion-induced stress in recent years is reviewed from different levels of the active particle, the active electrode, the half-cell, the cell unit, and the cell. The generation mechanism and research methods of diffusion-induced stress are introduced. The influence of diffusion-induced stress on the mechanical and electrochemical properties of the battery is analyzed, and the influencing factors of the diffusion-induced stress are summarized. Finally, the future research directions and development trends are prospected.

Anode material is an important component for Li-ion battery. The current anode materials are mainly based on graphite, which possesses low theoretical specific capacity of 372 mAh/g, and thus hinder the further development of Li-ion battery. Among the newly developed anode materials, metal oxides have recently attracted intense attention due to their high theoretical specific capacity, low cost and environmental friendliness. However, metal oxides own poor electrical conductivity and large volume changes during cycling. Nanosizing can overcome these disadvantages while maintaining the advantages for metal oxide based anode materials, and thus becomes a research hot spot. Herein, we review the recent research advances of the nanostructured metal oxides as anode materials, mainly focusing on the microstructure design and performance optimization of representative metal oxides and their composites. In addition, some suggestions are presented for further explorations in relative fields.

In recent years, the development of new energy vehicles industry is accelerating. Lithium nickel cobalt manganese/aluminum oxide ternary cathode materials (NCM/NCA), especially with the nickel content ≥50%, has aroused great interest in both academia and industry. This is mainly due to the fact that the aggregative parameters of performance and cost of NCM/NCA are superior to those of traditional cathode materials, such as LiCoO₂ and LiFePO₄. However, the application of NCM/NCA is affected by a number of drawbacks, including poor safety and insufficient cycle stability and so on, which are mainly attributed to its crystal and surface structure. Researchers have carried out various efforts to solve these problems and further improve the performance of NCM/NCA. Some remarkable results have been achieved in the past few years. In this review, the latest research progress on coating and doping of Ni-rich ternary cathode materials is summarized from the view on the mechanism of structural and electrochemical improvement of NCM/NCA. Finally, the perspective for the development of NCM/NCA cathode materials is also prospected.

Due to competitive theoretical capacity, Bi₂Mn₄O₁₀ has been deemed as an efficient Li-ion battery anode material. Bi₂Mn₄O₁₀ powder was prepared by polyacrylamide gel method using bismuth nitrate and manganese acetate as raw materials. The effects of preparation conditions on the phase, morphology and electrochemical cycling performance of powder were investigated. Results showed that the spheroid Bi₂Mn₄O₁₀ powder with narrow size distribution was successfully prepared under the conditions of molar ratio of acrylamide to total metal ions of 8 : 1, the glucose concentrations of 1.11 mol/L and heat treatment temperature of 873 K. Lithium ion batteries with as-prepared Bi₂Mn₄O₁₀ as anode material, acquired excellent cycle and rate performances. Its discharge specific capacity is 496.8 mAh/g at 0.2C (1C=800 mA/g) rate after 50 cycles, corresponding to a high capacity of 76.9%. Even at 3C rate, a superior rate capacity of 232 mAh/g is retained.

Organic/inorganic composites have been considered as promising electrolyte candidates in all solid-state lithium batteries. Aiming at improving the conductivity significantly by increasing the frequently-used 0D or 1D ceramic nano-fillers to high content is unsuccessful due to the particle tendency to agglomeration. What's worse, the loose contact between the solid electrolyte and solid electrodes is much of a serious barrier to the performance and thus to the application of all solid-state lithium batteries. Herein, self-supported 3D porous Li_6.4Al_0.1La₃Zr_1.7Ta_0.3O₁₂ frameworks are employed to provide percolated fast Li⁺ conductive pathway while in-situ polymerization of poly(ethylene glycol) methyl ether acrylate can integrate the loose solid-solid interface and reduce the interfacial resistance efficiently. Inspiringly, the Li⁺ conductivity of the composite exhibits 1.9×10^-4 S·cm^-1 at room temperature. The interfacial resistance in Li-Li batteries decreases significantly from 1540 to 449 Ω·cm ², rendering good capacity and cyclability of the 4.3 V (vs. Li⁺/Li) LiCoO₂|Li all solid-state lithium battery.