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. Li₂ S₆ is converted into thiosulfate and polythionate by a catenation reaction on the interfacial boundary of CoC₂ O₄ contacted with carbon. Following this, the active polythionate and short-chained liquid lithium polysulfides (LiPS) bound to the cobalt surface are further reduced as CoC₂ O₄ reduces the overpotential to facilitate the LiPS redox reaction, leading to high specific capacity, lower self-discharge rate, and stable long-term cycling performance.