Stabilising graphite anode with quasi-solid-state electrolyte for long-life lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries with high energy density are promising for next-generation energy storage but suffer from poor cycle life due to instability of the lithium anode. Commercial graphite anodes used in lithium-ion batteries could be viable for replacement of lithium metal as anode in Li-S batteries. However, graphite anodes are incompatible with the commonly used ether-based electrolytes in Li-S batteries due to the Li⁺ ion and solvent co-intercalation into graphite interlayers, which leads to exfoliation. Here, we report the stabilisation of graphite anode by in-situ formation of quasi-solid-state electrolyte (QSSE) in Li-S batteries. The QSSE is formed by the ring-opening of molecular ethers induced by metallic molybdenum disulfide sulfur cathode host to produce long-chain polymers. The resulting gel polymer matrix exhibits ionic conductivity (1.51 mS cm^-1) comparable to that of liquid electrolyte and provides sufficient redox chemistry for the sulfur cathode without co-intercalation into the graphite anode. Li-S pouch cells based on in-situ formed QSSE and graphite anode show a specific capacity of ~ 1200 mAh g^-1 and 90.3% capacity retention after 200 cycles. Our design addresses the electrolyte limitation associated with graphite anode, enabling graphite to be used in ether-based solvents for safe, cost-effective and stable Li-S batteries.

The online version contains supplementary material available at 10.1557/s43581-025-00139-0.