High Performance Porous Silicon Anode Synthesized by LowTemperature Aluminothermic Reaction

In this work, we developed a new aluminothermic reduction reaction that uses a eutectic mixture ofAlCl۳ and ZnCl۲ as the mediator. AlCl۳ (m.p. ~۱۰۹۱C) and ZnCl۲ (m.p. ~۲۰۹۱C) forms a eutectic mixturearound the composition of ۹۵۵۲ mole fraction of ZnCl۲ with the melting point of ۱۱۶ ± ۲ °C. It not onlyserves as the reaction media, but also enables the aluminothermic reduction to be done through the uniquereaction route at a temperature as low as ~۱۸۹ °C. Furthermore, the addition of ZnCl۲ makes the mixtureless sensitive to ambient moisture, thus more convenient for handling. With carbon precoating on the porousSiO۲ precursor, porous Si@C core shell structured anodes could be obtained with structure and morphologysimilar to that of the porous precursor. Therefore, this work represents a new low-cost approach for Sisynthesis and represents a step forward for the development of Si anodes for high-energy-density lithium ionbatteries.

Keywords:

Silicon anode , Aluminothermic reaction , AlCl۳ , ZnCl۲ , Si@C , Lithium ion battery