Graphite–Lithium Sulfide Battery with a Single-Phase Sparingly Solvating Electrolyte

This is the first practical demonstration of a next-generation graphite–Li2S battery using a high-load Li2S cathode on a porous current collector and a small amount of a single electrolyte. Li2S is a promising cathode material for Li–S batteries, but it must be mixed with a conductive substrate owing to its insulating properties. We prepared Li2S/C composites using commercially available carbon-based materials as carbon hosts and agents for the reduction of a Li2SO4 precursor to Li2S. Intimate contact between the Li2S/C composite constituents was achieved in situ with the additional carbon-based material. The specific surface area of the carbon-based precursor affected the electrochemical performance of the Li2S/C composite. Using a sparingly solvating electrolyte enabled highly reversible electrochemical graphite intercalation and suppressed the polysulfide shuttling effect owing to a reduction in lithium polysulfide intermediate solubility. The graphite–Li2S full cell exhibited high Coulombic efficiency and stable long-term cycling performance.