The Application of Magnesiothermic Reduction of Silica to Produce Porous Silicon for Lithium Ion Batteries

Abstract

Increasing demand for portable power applications are pushing conventional battery chemistries to their theoretic limit. Silicon has the potential as an anode material to increase lithium-ion cell capacity. The associated volume change of lithiation leads to a decline in capacity during cycling and low lithium diffusion rates within silicon limit high rate discharging. Many silicon morphologies and nanostructures have been studied including porous architectures. Porous morphologies can potentially address the poor cyclability and rate capabilities simultaneously. The template assisted synthesis ‘magnesiothermic reduction’ of silica to silicon offers a facile and scalable synthesis route to porous silicon structures. However, our review of the recent progress of this method indicates a distinct lack of mechanistic understanding of this phenomenon. To better understand the processes, we have systematically studied the process conditions using a model silica system. Further, we performed a complete characterisation of both the reactant and product structures in order to map how reaction conditions affect the properties of the electrode materials. Finally, we will present the battery performance of these porous silicon structures and compile a processing-structure-property-performance relationship. Figure 1