A high-entropy metal oxide as chemical anchor of polysulfide for lithium-sulfur batteries

Abstract

Lithium-sulfur (Li-S) battery is anticipated as one of the most promising candidates for the next-generation rechargeable cell. In order to conquer the shuttle effect of dissolution lithium polysulfides (LIPSs), the chemical interactions between sulfur host and LIPSs on the performance of Li-S batteries has recently been highlighted. Herein, a facile strategy is proposed, which produces a high-entropy metal oxide (HEMO-1) as an anchor to restrain LIPSs in Li-S batteries via chemical confinement as demonstrated by strong bonding interaction between HEMO-1 and Li2S6. The as-prepared HEMO-1 incorporates five metal components, Ni, Mg, Cu, Zn and Co, into a metal oxide crystalline structure. The homogeneously dispersive multiple metal active species in HEMO-1 favor the restriction of LIPSs and facilitate the redox reaction in the cathode of Li-S batteries. Especially, the synergistic contribution of Li-O and S-Ni bonds from the interaction between HEMO-1 and LIPSs effectively alleviate the shuttle of LIPSs between the cathode and anode. As the promoter catalyst for LIPSs, HEMO-1 shows a competitive reversible capacity, outstanding cycling stability, and a low capacity decay of 0.077% per cycle after 600 cycles. This study not only presents a high-entropy oxide promoter for polysulfide immobilizing in Li-S batteries, but also provides an avenue of high-entropy metal oxides to a variety of energy conversion and storage fields.