Desolvation Synergy of Multiple H/Li-Bonds on an Iron-Dextran-Based Catalyst Stimulates Lithium-Sulfur Cascade Catalysis.

Abstract

Traditional lithium-sulfur battery catalysts are still facing substantial challenges in solving sulfur redox reactions, which involve multistep electron transfer and multiphase transformations. Here, inspired by the combination of iron dextran (INFeD) and ascorbic acid (VC) as a blood tonic for the treatment of anemia, a highly efficient VC@INFeD catalyst is developed in the sulfur cathode, accomplishing the desolvation and enrichment of high-concentration solvated lithium polysulfides at the cathode/electrolyte interface with the assistance of multiple H/Li-bonds and resolving subsequent sulfur transformations through gradient catalysis sites where the INFeD promotes long-chain lithium polysulfide conversions and VC accelerates short-chain lithium polysulfide conversions. Comprehensive characterizations reveal that the VC@INFeD can substantially reduce the energy barrier of each sulfur redox step, inhibit shuttle effects, and endow the lithium-sulfur battery with high sulfur utilization and superior cycling stability even under a high sulfur loading (5.2mg cm-2 ) and lean electrolyte (electrolyte/sulfur ratio, ≈7µL mg-1 ) condition.