Comparative study of bulk and nano-structured mesoporous SnO2 electrodes on the electrochemical performances for next generation Li rechargeable batteries

Abstract

For next generation Li-ion batteries, advanced electrode materials with high energy densities are mightily important issue. Since the partial oxidation of Sn with Li2O to form SnOx was demonstrated upon delithiation in SnO2 anode, the additional conversion reaction has contributed that the theoretical capacity of SnO2 can be extended from 783 to 1494 mAh g−1. Herein, with the design of additional conversion reaction, we discuss key factors for high electrochemical performances of the SnO2 anodes through comparative analysis between nano-structured mesoporous SnO2 and conventional bulk SnO2, based on synchrotron radiation-based techniques, quantitative analysis of extended X-ray absorption fine structure spectra, and bond strength calculation. In this way, we demonstrate that the mesoporous SnO2 has a nano-engineered structure with the weakened Sn-O bond strength for inducing the enhanced reversible conversion reaction as well as the facilitated electrochemical reaction, and a void structure for relieving the severe volume changes during lithiation/delithiation. Consequently, excellent electrochemical performance through the additional reversible conversion reaction is obtained in the mesoporous SnO2. Insight from this research enables important advance in the development of metal oxide-based anode materials by making irreversible reaction reversible, providing a realizable strategy for the design and creation of high-energy storage devices.