A Phyllostachys Edulis -Derived Microporous Carbon-Coated Separator with Improved Li+ Transport for Long Cycling Lithium–Chalcogenide Batteries

Abstract Lithium–chalcogenide batteries (LCBs) offer high theoretical energy density but suffer from the polysulfide/polyselenide shuttling during charging and discharging processes with conventional polypropylene (PP) separators, causing low active-material utilization and severe capacity decay. Herein, we develop a Phyllostachys edulis bamboo-derived microporous carbon-coated PP separator (MPC@PP) to suppress polychalcogenide migration and enable long-term cycling. The abundant micropores in the MPC coating enhance polysulfide adsorption and boost the Li+ transference number to 0.57, which is a 46.2% increase over pristine PP (0.39). The lithium symmetric Li/Li cell with MPC@PP exhibits good cycling stability up to 300 h at 0.5 mA cm–2 (1 mAh cm–2) with a smooth and compact lithium deposition. When used in Li–S battery with the S@Ketjenblack cathode, the MPC@PP cell delivers a reversible capacity of 1272.92 mAh g–1 at 167.5 mA g–1 and stable cycling over 500 cycles at 837.5 mA g–1. Moreover, Li–SeS2 battery with MPC@PP achieves an initial capacity of 723.48 mAh g–1 at 1342 mA g–1 with average Coulombic efficiency >99.2% for 500 cycles. This work provides a cost-effective and scalable biomass-derived microporous carbon strategy to address the critical challenges of LCBs, offering valuable guidance for advanced separator design and accelerating the deployment of high-energy-density rechargeable batteries.