Zigang Wang

Due to its extremely high theoretical mass specific capacity, silicon is considered to be the most promising anode material for lithium-ion batteries (LIBs). However, serious volume expansion and poor conductivity limit its commercial application. Herein, dealloying treatments of spray dryed Al-Si-Cu-Ni particles are performed to obtain a Cu/Ni co-doped Si-based anode material with a porous nanowire network structure. The porous structure enables the material to adapt to the volume changes in the cycle process. Moreover, the density functional theory (DFT) calculations show that the co-doping of Cu and Ni can improve the capture ability towards Li, which can accelerate the electron migration rate of the material. Based on the above advantages, the as-prepared material presents excellent electrochemical performance, delivering a reversible capacity of 1092.4 mAh g⁻¹ after 100 cycles at 100 mA g⁻¹. Even after 500 cycles, it still retains 818.7 mAh g⁻¹ at 500 mA g⁻¹. This study is expected to provide ideas for the preparation and optimization of Si-based anodes with good electrochemical performance.

As high-capacity anode materials, spinel NiFe₂O₄ aroused extensive attention due to its natural abundance and safe working voltage. For widespread commercialization, some drawbacks, such as rapid capacity fading and poor reversibility due to large volume variation and inferior conductivity, urgently require amelioration. In this work, NiFe₂O₄/NiO composites with a dual-network structure were fabricated by a simple dealloying method. Benefiting from the dual-network structure and composed of nanosheet networks and ligament-pore networks, this material provides sufficient space for volume expansion and is able to boost the rapid transfer of electrons and Li ions. As a result, the material exhibits excellent electrochemical performance, retaining 756.9 mAh g⁻¹ at 200 mA g⁻¹ after cycling for 100 cycles and retaining 641.1 mAh g⁻¹ after 1000 cycles at 500 mA g⁻¹. This work provides a facile way to prepare a novel dual-network structured spinel oxide material, which can promote the development of oxide anodes and also dealloying techniques in broad fields.

Metal oxide anode materials are affected by severe volume expansion and cracking in the charging/discharging process, resulting in low capacity and poor cycle stability, which limits their application in lithium-ion batteries (LIBs). Herein, a new strategy is uncovered for a preparing spinel-structured, multi-component transition metal oxide, (Ni,Co,Mn)Fe₂O_4−x, with oxygen vacancies as an LIB anode material. The as-fabricated material presented excellent reversible capacity and cycling stability, delivering a discharge capacity of 1240.2 mAh g⁻¹ at 100 mA g⁻¹ for 200 cycles and then at 300 mA g⁻¹ for 300 additional cycles. It presented extremely long cycle stability even at 2 A g⁻¹, revealing 650.5 mAh g⁻¹ after 1200 cycles. The good lithium storage capacity can be ascribed to the entropy stabilization effect, the multi-cation synergistic effect, abundant oxygen vacancies and the spinel structure. This study provides a new opportunity to fabricate and optimize conversion-type anodes for LIBs with satisfactory electrochemical performance.