Sulfur‐doped shaddock peel–derived hard carbons for enhanced surface capacity and kinetics of lithium‐ion storage

Sulfur doping has been regarded an energetic route to optimize the lithium storage properties of carbon-based electrode materials. In this work, sulfur-doped shaddock peel–derived hard carbon is successfully prepared by a KOH- and C2H5NS-assisted pyrolysis procedure. It is demonstrated that sulfur doping has strong effect on surface activation and graphitization enhancement, which results in the significant enhancement of the surface adsorption capacity and reaction kinetics of the hard carbon materials. When employed as a lithium ion batteries (LIBs) anode, the as-obtained hard carbon demonstrates excellent cycling and rate properties, presenting a great specific capacity of 738 mAhg−1 at 50 mAg−1 after 200 cycles, as well as 491 mAhg−1 at 200 mAg−1 after 300 cycles. Even at 1000 and 2000 mAg−1, the hard carbon provides a large rate capacity of 283 and 179 mAhg−1, respectively. Besides, it is revealed that the Li+ storage process is determined by the surface-induced pseudocapacitive process, whose capacitive proportion reach 60% at 0.5 mVs−1. This work suggests that the low cost and eco-friendly sulfur-doped shaddock peel–derived hard carbon is a very prospective LIB anode material.