Tailored Reaction Route by Micropore Confinement for Li-S Batteries Operating under Lean Electrolyte Conditions

Lithium-sulfur (Li-S) batteries are one of the most promising alternative energy storage systems beyond Li-ion batteries. However, the sluggish kinetics of the nucleation and growth of the solid discharge product of Li2S/Li2S2 in the lower discharge plateau has been recently identified as a critical hurdle for attaining high specific capacity in Li-S batteries with high sulfur loadings under lean electrolyte conditions. Herein, a new strategy of breaking the charge-transport bottleneck by successful generation of experimentally verified stable Li2S2 and a reservoir of quasi-solid lithium polysulfides within the micropores of activated carbon fiber cloth as a high-sulfur-loading host is proposed. The developed Li-S cell is capable of delivering a highly sustainable areal capacity of 6.0 mAh cm(-2) under lower electrolyte to sulfur ratios (<3.0 mL(E) g(S)(-1)). Micropore confinement leads to generation of solid Li2S2 that enables high utilization of the entire electroactive area by its inherent self-healing capacity. This strategy opens a new avenue for rational material designs for Li-S batteries under lean electrolyte condition.