Lithium sulfide (Li2S) is one of the most promising cathode materials for the next-generation advanced lithium-ion batteries as it allows for the use of lithium-free metal-based high capacity Li-ion anodes such as silicon anode etc. It has high theoretical capacity (1167 mA h g-1) and large energy density to match with high capacity metal anodes. However, Li2S suffers from poor rate performance and short cycle life due to its insulating nature and polysulfide shuttle during cycling. In this work, we report a facile and viable approach to address these issues. We propose a bottom-up method to synthesize such a nanocomposite by dissolving Li2S as the active material, polyvinylpyrrolidone (PVP) as the carbon precursor, and graphene oxide as matrix to enhance the conductivity, followed by a co-precipitation and high-temperature carbonization process. The Li2S/rGO cathode yields an exceptionally high initial capacity of 858 mAh/g based on Li2S mass at C/9 rate and also shows a good cycling performance. The carbon coated Li2S/rGO cathode demonstrates the capability of robust core-shell nanostructures for different rates and improved capacity retention, revealing carbon coated Li2S/rGO designed as an outstanding system for high-performance lithium-sulfur batteries.

PVP-assisted synthesis of uniform carbon coated Li2S/rGO for high-performance lithium-sulfur batteries

255th National Meeting (2018)

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