Enhancing the Reversibility of Mg/S Battery Chemistry through Li+ Mediation

By Tao Gao and Malachi Noked and Alex J Pearse and Eleanor Gillette and Xiulin Fan and Yujie Zhu and Chao Luo and Liumin Suo and Marshall A Schroeder and Kang Xu and Sang Bok Lee and Gary W. Rubloff and Chunsheng Wang
Published in Journal of the American Chemical Society NULL 2015

Abstract

Mg metal is a promising anode material for next generation rechargeable battery due to its dendrite-free deposition and high capacity. However, the best cathode for rechargeable Mg battery was based on high molecular weight MgxMo3S4, thus rendering full cell energetically uncompetitive. To increase energy density, high capacity cathode material like sulfur is proposed. However, to date, only limited work has been reported on Mg/S system, all plagued by poor reversibility attributed to the formation of electrochemically inactive MgSx species. Here, we report a new strategy, based on the effect of Li+ in activating MgSx species, to conjugate a dendrite-free Mg anode with a reversible polysulfide cathode and present a truly reversible Mg/S battery with capacity up to 1000 mAh/gs for more than 30 cycles. Mechanistic insights supported by spectroscopic and microscopic characterization strongly suggest that the reversibility arises from chemical reactivation of MgSx by Li+.

Read » Back