Dual-functional SnO2-CNT-PANI||PP=|SnO2 separator for enhanced lithium-sulfur battery stability and capacity

Lithium-sulfur batteries (LSBs) provide high capacity and energy density for advanced energy storage but encounter performance and safety issues due to lithium polysulfides (LiPSs) dissolution and dendrite formation. This study introduces a dual-functional SnO 2 -CNT-PANI||PP=|SnO 2 separator (DF-SNCPS) aimed at improving the stability and safety of LSBs. The separator includes a SnO 2 -CNT-PANI layer on the sulfur cathode side for enhanced electrical conductivity and polysulfide adsorption and a SnO 2 nanoparticle (nano-SnO 2 ) layer on the lithium anode side to regulate lithium-ion concentration and inhibit dendrite growth. Density functional theory (DFT) and the phase field method have verified the relevant material's catalytic performance and dendrite suppression ability. These methods have provided a comprehensive understanding of the underlying mechanisms, providing auxiliary explanations for their role in catalyzing polysulfide conversion and suppressing lithium dendrite growth. This innovative design mitigates the shuttle effect and enhances cyclic stability and sulfur utilization, achieving a notable cyclic performance with a capacity retention of 0.05 % per cycle over 800 cycles at 1 C. The synergistic effects of the modified separator present a viable pathway for LSB commercialization.