Phyllostachys Edulis-Derived Nanoconfined Microporous Carbon-Sulfur Cathodes for High-Rate Lithium-Sulfur Batteries

The severe shuttle effect of polysulfides for high-performance lithium-sulfur (Li-S) batteries leads to poor reversibility and cyclability at high rates, greatly hindering their practical applications. Here, we design a Phyllostachys edulis-derived microporous carbon-sulfur (denoted as MPC@S) cathode with physical nanoconfinement and chemical C-S bonding for high-rate Li-S batteries. The high pore volume can physically confine sulfur and polysulfides into microporous carbon to achieve good structural stability of the electrode during cycling. Moreover, the strong chemical C-S bonding interaction between MPC and sulfur can effectively improve the utilization of the active material and enhance redox reaction kinetics at high rates. Due to the synergistic combination of physical and chemical confinement of sulfur and polysulfides, the Li-S battery with MPC@S cathode delivers an initial specific discharge capacity of 1070.06 mAh g^-1 at 167.5 mA g^-1 and achieves good cyclability with a high average Coulombic efficiency of >97.88% at 1675 mA g^-1 for 500 cycles with a low decay rate of 0.0912% per cycle. This work provides a facile strategy for the large-scale fabrication of high-performance biomass-derived composite cathodes for high-rate Li-S batteries and brings deep insights into structure-property relationships of high-capacity electrodes for next-generation lithium batteries.