Hierarchical Nanowire Host Material for High-Areal-Capacity All-Solid-State S/SeS2 Batteries

Abstract

All-solid-state sulfur batteries (ASBs) suffer from electrical and ionic conduction problems due to the insulating sulfur. By comparing three host materials with different structural characteristics, herein, carbon nanotubes (CNTs) decorated with a conductive metal sulfide (CoMoS2@CNT) is demonstrated, designed to host sulfur and exchange both Li-ions and electrons, effectively. In this hierarchical wire structure, porous CoMoS2 nanosheets form close interfaces with sulfur, and the CNT core directly transfers electrons to the sulfur-impregnated CoMoS2. Simultaneously, the solid electrolyte positioned on the outer region of the nanowire material ensures facile Li-ion conduction to the sulfur-impregnated CoMoS2. An ASB featuring a CoMoS2@CNT host material with a sulfur loading of 3 mg cm−2 exhibits a high-areal-capacity of 4.5 mAh cm−2 at a current density of 2.5 mA cm−2, while retaining 79.4% of its initial capacity after 300 cycles. When sulfur is replaced with SeS2 to further reinforce the charge conduction properties, all-solid-state SeS2 batteries (ASeS2Bs) with an extremely high-areal-capacity of 16.3 mAh cm−2 retain 99.3% of their initial capacities after 60 cycles at 60 °C. This study provides guidelines for the design principles of cathode composites for the ASBs and ASeS2Bs through multiangle comparative analysis.