Bifunctional NiCo2S4 catalysts supported on a carbon textile interlayer for ultra-stable Li–S battery

Abstract

Lithium–sulfur (Li–S) batteries with high energy density and natural abundance are critical to achieve the low-cost and large-scale energy storage applications. Suffering from the sluggish redox kinetics together with the accumulated intermediate Li₂S_x (x = 4–8) polysulfides in the liquid electrolytes during charging/discharging, the high-performance Li–S batteries are stagnant by the issues such as high level of electrochemical irreversibility and poor cyclability. Herein, a bifunctional interlayer composed of metallic conductive NiCo₂S₄ nanosheets with large area and mesopores supported on carbon textile (NiCo₂S₄@CT) is fabricated for high-performance Li–S batteries. The mesoporous and metallic conductive NiCo₂S₄ nanosheets with large area not only provide strong chemical bonding for polysulfides, but also show efficient catalytic effect towards accelerating the polysulfide redox reactions. When served as an interlayer, NiCo₂S₄@CT endows the Li–S batteries with a high initial capacity of ∼1600 mA h g⁻¹ at 0.1C and ultra-stable cycling performance with a slow capacity decay rate of 0.018% per cycle over 500 cycles. The results proffer a facile and promising approach to design Li–S batteries with high rate performance and high reversible capacities.