Accelerating the catalytic conversion of lithium polysulfides in lithium sulfur batteries via NiV-LDH/CNT

Abstract

To address the critical challenges of polysulfide shuttle effects and sluggish redox kinetics in lithium-sulfur batteries (LSBs), this study synthesizes a nickel-vanadium layered double hydroxide/carbon nanotube (NiV-LDH/CNT) composite cathode material through a one-step hydrothermal method, as efficient electrocatalysts for LSBs. SEM and BET tests show that the NiV-LDH/CNT composite material increase the specific surface area and exposes more active sites, providing space for sulfur storage and alleviating sulfur volume expansion. Meanwhile, theoretical calculations indicate that NiV-LDH/CNT lowers the reaction energy barrier for lithium polysulfides (LiPSs), effectively accelerating the redox reactions of LiPSs. As a result, the NiV-LDH/CNT electrode demonstrates stable cycling performance, achieving a high initial specific capacity of 1091.7 mAh g^-1 at 1.0 C with a capacity decay rate of only 0.07% per cycle in 800 cycles. Even under harsh conditions (with a sulfur loading of 7.1 mg cm^-2 and an E/S ratio of 6.0 μL mg^-1), an initial specific capacity of 1000.9 mAh g^-1 can still be achieved. This design overcomes the limitations of traditional carbon-based cathodes reliant on physical confinement alone, offering a novel strategy to advance the practical implementation of high-energy-density LSBs.