Approaching high rate All-Solid-State Lithium-Sulfur batteries via promoted sulfur conversion with nickel oxide nanoparticle electrocatalyst

Abstract

All-solid-state lithium-sulfur battery (ASLSB) is deemed a promising next-generation energy storage device owing to its combination of high theoretical specific energy (2600 Wh kg−1) derived from the sulfur active material, and exceptional safety characteristics and the ability to suppress the polysulfide shuttle effect through the use of solid electrolyte (SE). However, the low electronic and ionic conductivity of sulfur, coupled with the poor solid–solid interfacial contact inherent in all-solid-state configuration, has resulted in poor electrochemical performance. Herein, NiO electrocatalyst supported on N-doped sites of super-p was synthesized and incorporated as a carbon additive in the composite cathode of the ASLSB. The direct growth of nanosized NiO electrocatalyst on the N-doped sites of super-p ensures facile electron transfer to the electrocatalyst surface, while maximizing the electrocatalyst’s surface area. As a result, the overpotential during charging and discharging of the ASLSB was significantly reduced, as assessed through galvanostatic intermittent titration technique and cyclic voltammetry, indicating enhanced redox conversion of sulfur. Furthermore, the Li6PS5Cl sulfide SE induces solid–solid conversion of sulfur, eliminating the dissolution issue of polysulfide intermediates and ensuring good cycle performance. The assembled ASLSB exhibits a high reversible capacity of 1845 mAh g−1 at 0.05C at room temperature and enhanced rate capability at high C-rates, operated at 60 °C. Even at a substantially high sulfur loading level of 6.65 mg cm−2, a maximum areal capacity of 9.48 mAh cm−2 was achieved at room temperature, highlighting the important role of electrocatalyst in realizing high performance ASLSBs.