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As a promising candidate for the next generation of new anode materials, the modification and optimization of silica-based anode materials are significant. Using chitosan (CS) as the carbonaceous precursor, the N-containing Si@C microcapsules were prepared by emulsification cross-linking combined with high-temperature pyrolysis method. The microcapsule structure offers additional space for nano-Si and effectively enhances the electrochemical properties of the anode. Moreover, optimizing the CS:Si ratio is advantageous in achieving a synergistic effect between silicon and carbon. When CS:Si = 4:1, the first specific capacity was 762.78 mAh/g and the retention rate was 69.27 % after 100 cycles. To further enhance the material properties, urea was added to a ratio of CS:Si = 4:1 as an N supplement for elemental doping modification. The specific capacity of the anode had a positive correlation with N content within a certain range. As the N content increases, the pyridine-N content and density of C vacancies also increase, which improves the storage form and diffusion path of Li+. When 0.75 g urea was added, the first reversible specific capacity reached 1108.88 mAh/g and the retention rate was 92.41 % after 100 cycles. This work offers environmentally friendly and safe methods, as well as a new modification concept for N-doped microsphere-encapsulated silicon-carbon composites. • Microcapsule structure provides additional physical buffer space. • Chitosan as biomass polymers containing N. • Nanosilicon diffusely distributed inside the carbon shell. • The increase of N can optimize the storage form and diffusion path of Li+. [ABSTRACT FROM AUTHOR]

• Novel molybdenum-based cathode materials Li 2 O -MoO 3 -V 2 O 5 -P 2 O 5. • [MoO6], [PO4] and [VO4] co-form a stabilized amorphous structure. • Suppressing Mo5+/Mo4+ conversion improves cycling stability. Li 2 O-MoO 3 -P 2 O 5 and Li 2 O-MoO 3 -V 2 O 5 -P 2 O 5 amorphous cathode oxides were prepared using a simple melt quenching technique. The discharge-specific capacity of the 2Li 2 O-5MoO 3 -V 2 O 5 -2P 2 O 5 after 100 cycles was 141.43 mAh/g, with a capacity retention rate of 77.27 %, while the discharge-specific capacity of the 2Li 2 O-6MoO 3 -2P 2 O 5 after 100 cycles was 100.52 mAh/g, with a capacity retention rate of 55.78 %, in the voltage range of 1.5–4.2 V and at a current density of 10 mA/g. According to the findings, vanadium pentoxide may help molybdenum-based amorphous cathodes perform better electrochemically. In particular, the Mo5+/Mo4+ transition is inhibited, and the Mo6+/Mo5+ transition is promoted by the presence of the V5+/V4+ transition in the charge/discharge cycle of the Li 2 O-MoO 3 -V 2 O 5 -P 2 O 5 amorphous material, shortening the structural self-regulation process in the electrochemical cycle and significantly increasing cycle stability. The study provided a new idea for investigating novel cathode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• Glass with a high vanadium content improved the migration efficiency of Li+. • Adding Fe 2 O 3 stabilized the structure and increased the contents of V3+ and V4+. • The cathode has the outstanding specific capacity and high-current response. Among new lithium-ion battery cathode materials, amorphous materials show unique advantages and vanadium-based materials are potential electrode materials. In our study, the vanadium-based Li 2 O-V 2 O 5 -B 2 O 3 glassy state electrode materials with high vanadium contents were prepared in air by the melt-quenching method. The structures and electrochemical performances of glass materials were investigated by various characterization methods. The Li 2 O-V 2 O 5 -B 2 O glass were mainly connected with VO 4 and BO 3 structural units to form a disordered network structure. The first discharge capacity of 20Li 2 O-60 V 2 O 5 -20B 2 O 3 glass cathode material reached 168.6 mAh/g at a current density of 100 mA/g. The conversion of V3+/V4+ and V4+/V5+ mainly occurred in the charge and discharge cycles. When 10% of B 2 O 3 was replaced by Fe 2 O 3 , the compactness and stability of the material were improved. Furthermore, with the addition of Fe 2 O 3 , the concentrations of low-valence V4+, V3+ and Fe2+ ions increased, thus contributing to the electrochemical performance. The specific capacity of 20Li 2 O-60V 2 O 5 -10B 2 O 3 -10Fe 2 O 3 cathode material increased significantly and the first discharge capacity was as high as 306.2 mA h/g at a current density of 100 mA/g. However, the specific capacity respectively decreased to 239 mA h/g in the second cycle and 120.3 mA h/g after 100 cycles. The study on vanadium-based glass cathode materials provided a new idea for the investigation of novel cathode materials for lithium-ion batteries. [ABSTRACT FROM AUTHOR]