LDH-derived Co0.5Ni0.5Te2 dispersed in 3D carbon sheets as a separator modifier to enable kinetics-accelerated lithium–sulfur batteries†

Abstract

Lithium–sulfur batteries are considered powerful candidates for the next generation of advanced energy-storage systems owing to their high energy density and theoretical specific capacity. However, their practical commercial feasibility has been hampered by their sluggish kinetics and severe shuttle effect. Hence, a novel hybrid comprising NiCo-LDH-derived Co_0.5Ni_0.5Te₂ nanoparticles grafted on 3D carbon sheets was rationally constructed through facile steps and served as a functional separator modifier for a lithium–sulfur battery. It was found that the 3D cross-linked conductive network structure of the hybrid is conductive to continuous electron transfer. In addition, well-dispersed Co_0.5Ni_0.5Te₂ nanoparticles with hexahedral morphology offer an ample sulfophilic surface to chemically anchor and catalyze the redox dynamics of sulfur species. It was proven that the dynamic conversion of sulfur-involved reactions was effectively promoted and the utilization of polysulfides was boosted. The related cells demonstrated attractive long-cycling durability (784.8 mA h g⁻¹ at 2 C after 500 cycles) and an excellent rate performance (699.5 mA h g⁻¹ even at 7 C). Furthermore, when sulfur loading reached 6.89 mg cm⁻², areal capacity could still be maintained at 6.40 mA h cm⁻² after 50 cycles at 0.2 C. This work provides a promising strategy to design a multifunctional separator modifier and promotes the exploration of metal tellurides to engineer advanced kinetics-accelerated lithium–sulfur batteries.