Propelling the polysulfide phase transformation of lithium-sulfur battery by VO2-rGO

Rather than preventing the dissolution and diffusion of polysulfides, promoting polysulfide conversion through improved polysulfide redox is another promising strategy to suppress the dissolution of polysulfides and enhance the cycle life of sulfur cathodes. We demonstrated that VO2-rGO not only facilities liquid-involving polysulfide redox (Li2S8 -> Li2S6 -> Li2S4), but also promotes the effective decompositions of lithium sulfide (Li2S). As evidenced by the visual experiments and DFT calculation, VO2-rGO has strong affinity for polysulfides species. With sulfur loading of 2.15 mg cm(-2) and sulfur content of 76 wt%, the reversible capacity retained at 896 mAh g(-1) after 200 cycles. (C) 2019 Elsevier B.V. All rights reserved.