Interfacial architectures based on a binary additive combination for high-performance Sn4P3 anodes in sodium-ion batteries

Abstract

We demonstrate the important strategy to design suitable electrolyte systems that make the desirable interfacial structure to allow the reversible sodiation/desodiation of Sn<inf>4</inf>P<inf>3</inf> anodes. Our investigation reveals that the remarkable improvement in the electrochemical performance of Sn<inf>4</inf>P<inf>3</inf> anodes for NIBs is achieved by the combination of fluoroethylene carbonate (FEC) with tris(trimethylsilyl)phosphite (TMSP). We clearly present the unique functions of this binary additive combination to build up a protective surface film on the Sn<inf>4</inf>P<inf>3</inf> anode against unwanted electrolyte decomposition and to prevent the formation of the Na<inf>15</inf>Sn<inf>4</inf> phase, which is accompanied by a large volume expansion during the Na insertion (sodiation) process. ⓒ The Royal Society of Chemistry 2015