Reaction pathway and wiring network dependent Li/Na storage of micro-sized conversion anode with mesoporosity and metallic conductivity

Abstract

Micro-sized or monolithic electrode materials with sufficient mesoporosity and a high intrinsic conductivity are highly desired for high-energy batteries without the trade-off of electrolyte infiltration and accommodation of volume expansion. Here metallic nitrides consisting of mesoporous microparticles were prepared based on a mechanism of solid–solid phase separation and used as conversion anodes for Li and Na storage. Their superior capacity and rate performance during thousands of cycles benefit from the preservation or self-reconstruction of hierarchically conductive wiring networks. The conversion efficiency is also highly dependent on the reaction pathway and product. Exploring more conductive and percolating mass/charge transport networks particularly in a deep sodiation state is a potential solution for activation of Na-driven conversion electrochemistry.