Granadilla-Inspired Structure Design for Conversion/Alloy-Reaction Electrode with Integrated Lithium Storage Behaviors.

Abstract

Conversion/alloy-reaction electrode materials promise much higher energy density than the commonly used ones based on intercalation chemistries. However, the low electronic conductivity and, specially, the large volume expansion upon lithiation hinder their practical applications. Here, for the first time, a unique granadilla-inspired structure was designed to prepare the conversion/alloy-reaction anode of carbon coated tin/calcium tin oxide (C@void@Sn/CaSnO3) ternary composite. The granadilla-inspired structure ensures the intimate contact between the Sn/CaSnO3 nanoparticles and the carbon matrix, providing not only conductive networks for electron transport and a short distance for Li+ diffusion but also effective space for the electrode volume expansion toward conversion/alloy reaction. Moreover, the unique structure possesses abundant solid-solid interfaces between the three components as well as solid-liquid interfaces between nanoparticles and electrolyte, contributing to a large percent (58%) of interfacial charge (thus capacity). The integration of alloy-reaction, conversion-reaction, and interfacial lithium storage endows the hybrid electrode with a high capacity and long cycling life, holding great promise for next-generation high-capacity lithium-ion batteries.