Highly sulfiphilic zinc selenide/carbon regulators for high-capacity and long-lifespan Li-S batteries

Abstract

Lithium-sulfur (Li-S) batteries represent an attractive energy storage technology for the employment in next-generation high-energy–density rechargeable batteries. The main challenge is to increase the electrochemical utilization and stabilization of sulfur cathodes by mitigating the undesirable soluble polysulfide shuttle problem. Herein, a zinc selenide/carbon hybrid (ZnSe/C) is constructed as a regulator of commercial polypropylene (PP) separator to modify the sulfiphilicity of polysulfide species. It is revealed that the polar ZnSe/C hybrid greatly inhibits the shuttling effect by strong chemisorption and thereafter fast electrocatalytic transformation of polysulfides. Accordingly, the ZnSe/C-modified PP separator could kinetically expedite the redox reaction and effectively promotes the utilization and confinement of the active sulfur in the cathode side. As a consequence, the ZnSe/C-PP-cell exhibits excellent electrochemical properties, including an impressive capacity delivery of 1458/605 mAh g−1 at 0.1 C/5 C and long lifetime with 608 mAh g−1 retained after 1000 cycles at 1 C. This study paves a rational pathway for designing and propelling transition-metal-selenide electrocatalysts toward the practical application of Li-S batteries.