From sand to fast and stable silicon anode: Synthesis of hollow Si@void@C yolk–shell microspheres by aluminothermic reduction for lithium storage

Alloy-Type Anodes for High-Performance Rechargeable Batteries

Alloy-type anodes are one of the most promising classes of next-generation anode materials due to their ultrahigh theoretical capacity (2-10 times that of graphite). However, current alloy-type anodes have several limitations: huge volume expansion, high tendency to fracture and disintegrate, an unstable solid-electrolyte interphase (SEI) layer, and low Coulombic efficiency. Efforts to overcome these challenges are ongoing. This Review details recent progress in the research of batteries based on alloy-type anodes and discusses the direction of their future development. We conclude that improvements in structural design, the introduction of a protective interface, and the selection of suitable electrolytes are the most effective ways to improve the performance of alloy-type anodes. Furthermore, future studies should direct more attention toward analyzing their synergistic promoting effect.

A Stable Core–Shell Si@SiOx/C Anode Produced via the Spray and Pyrolysis Method for Lithium-Ion Batteries

In the critical situation of energy shortage and environmental problems, Si has been regarded as one of the most potential anode materials for next-generation lithium-ion batteries as a result of the relatively low delithiation potential and the eminent specific capacity. However, a Si anode is subjected to the huge volume expansion–contraction in the charging–discharging process, which can touch off pulverization of the bulk particles and worsens the cycle life. Herein, to reduce the volume change and improve the electrochemical performance, a novel Si@SiO_x/C anode with a core–shell structure is designed by spray and pyrolysis methods. The SiO_x/C shell not only ensures the structure stability and proves the high electrical conductivity but also prevents the penetration of electrolytes, so as to avoid the repetitive decomposition of electrolytes on the surface of Si particle. As expected, Si@SiO_x/C anode maintains the excellent discharge capacity of 1,333 mAh g⁻¹ after 100 cycles at a current density of 100 mA g⁻¹. Even if the current density reaches up to 2,000 mA g⁻¹, the capacity can still be maintained at 1,173 mAh g⁻¹. This work paves an effective way to develop Si-based anodes for high-energy density lithium-ion batteries.

Long-Term Stable Hollowed Silicon for Li-Ion Batteries Based on an Improved Low-Temperature Molten Salt Strategy

Nanostructured hollow silicon has attracted tremendous attention as high-performance anode materials in Li-ion battery applications. However, the large-scale production of pure hollowed silicon with long cycling stability is still a great challenge. Here, we report an improved low-temperature molten salt strategy to synthesize nanosized hollowed silicon with a stable structure on a large scale. As an anode material for rechargeable lithium-ion batteries, it exhibits a high capacity, excellent long cycling, and steady rate performance at different current densities. Especially, a high reversible capacity of 2028.6 mA h g^-1 at 0.5 A g^-1 after 150 cycles, 994.3 mA h g^-1 at 3 A g^-1 after 500 cycles, and 538.8 mAh g^-1 at 5 A g^-1 after 1200 cycles could be obtained. This kind of nanosized hollowed silicon can be applied as a basic anode material in silicon-based composites for long-term stable Li-ion battery applications.