High-rate performance of Li–S/Na–S batteries achieved by C/Sn composites with high active Sn atoms

Abstract

Li–S batteries and Na–S batteries attract wide attention because of high specific capacity, rich resources and environmental friendliness, but poor rate performance limits their development. Single atoms perform as active sites and promote redox reaction process of sulfur, which are benefit for improving rate performance of Li–S batteries and Na–S batteries. However, many researches only focus on transition metal atoms instead of non-transition metal atoms. Sn atoms are introduced on carbon surface to obtain C/Sn composites and electrochemical performance of C/Sn/S composites in Li–S batteries and Na–S batteries is studied in this paper. As for comparison, electrochemical performance of C/S without Sn atom modified is also studied. Results show that C/Sn/S composite electrodes possess higher rate performance than C/S composite electrodes in both Li–S batteries (359 mAh·g−1 at 20C) and Na–S batteries (151 mAh·g−1 at 20C). High-rate performance of C/Sn/S composite electrodes in Li–S batteries is attributed to catalytic abilities of active Sn atoms and high conductivity of carbon. Researches provide references for structure control and application of carbon composites with non-transition metal atom modified.