Improved Redox Reaction of Lithium Polysulfides on the Interfacial Boundary of Polar CoC2O4 as a Polysulfide Catenator for a High‐Capacity Lithium‐Sulfur Battery

Abstract The performance of cobalt oxalate as an electrocatalyst in a lithium‐sulfur battery (LSB) is improved owing to the suitable adsorbent properties of sulfur. The adsorption mechanism is elucidated by UV/Vis spectroscopy and surface analysis through X‐ray photoelectron spectroscopy. Li 2 S 6 is converted into thiosulfate and polythionate by a catenation reaction on the interfacial boundary of CoC 2 O 4 contacted with carbon. Following this, the active polythionate and short‐chained liquid lithium polysulfides (LiPS) bound to the cobalt surface are further reduced as CoC 2 O 4 reduces the overpotential to facilitate the LiPS redox reaction, leading to high specific capacity, lower self‐discharge rate, and stable long‐term cycling performance.