The formation of crystalline lithium sulfide on electrocatalytic surfaces in lithium–sulfur batteries

• Published in: Journal of energy chemistry Vol. 64; pp. 568 - 573
• Main Authors: Song, Yun-Wei, Qin, Jin-Lei, Zhao, Chang-Xin, Zhao, Meng, Hou, Li-Peng, Peng, Yan-Qi, Peng, Hong-Jie, Li, Bo-Quan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2022
• Subjects: Framework porphyrin; Lithium sulfide; Lithium–sulfur batteries; Polysulfide electrocatalysis; Sulfur redox reactions; Sulfur redox reactions; Polysulfide electrocatalysis; Lithium–sulfur batteries; Framework porphyrin; Lithium sulfide
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2021.05.023

Crystalline lithium sulfide is exclusively observed on electrocatalytic surface with uniform spherical morphology and preferentially participates in the discharge and charge processes in working lithium–sulfur batteries. [Display omitted] •Electrocatalytic surface reduces nucleation energy barrier to form crystalline Li2S.•Crystalline Li2S preferentially participates in the sulfur redox reactions with kinetic advantages.•Enhanced performances are achieved with crystalline Li2S in working Li–S batteries. Lithium–sulfur (Li–S) battery is highly regarded as a promising next-generation energy storage device but suffers from sluggish sulfur redox kinetics. Probing the behavior and mechanism of the sulfur species on electrocatalytic surface is the first step to rationally introduce polysulfide electrocatalysts for kinetic promotion in a working battery. Herein, crystalline lithium sulfide (Li2S) is exclusively observed on electrocatalytic surface with uniform spherical morphology while Li2S on non-electrocatalytic surface is amorphous and irregular. Further characterization indicates the crystalline Li2S preferentially participates in the discharge/charge process to render reduced interfacial resistance, high sulfur utilization, and activated sulfur redox reactions. Consequently, crystalline Li2S is proposed with thermodynamic and kinetic advantages to rationalize the superior performances of Li–S batteries. The evolution of solid Li2S on electrocatalytic surface not only addresses the polysulfide electrocatalysis strategy, but also inspires further investigation into the chemistry of energy-related processes.