Remediation of shuttle effect in a Li-sulfur battery via a catalytic pseudo-8-electron redox reaction at the sulfur cathode

Abstract

A catalytic pseudo-8-electron redox reaction of sulfur is achieved by facilitating the disproportionation of high-order polysulfide ions in a Li-Sulfur battery. Electrochemically generated polysulfide ions (Sx2-, where 3 < x < 7) undergo rapid disproportionation into elemental sulfur (S8) and Li2S2, catalyzed by a bifunctional carbon host/catalyst. The overall catalytic redox reaction at the sulfur cathode is represented as S8+8Li++8e⇌4Li2S2. In contrast to physical or chemical confinement methods for polysulfide ions, this approach remediates the shuttle effect by swiftly converting soluble polysulfides in the electrolyte to elemental sulfur and insoluble Li2S2 within the cathode matrix. As a result, the adverse chemical interaction between dissolved polysulfides and the Li anode is mitigated.

Keywords

• Li-S battery
• Polysulfide shuttle
• Bifunctional materials
• Disproportionation