Ni-plated viscose-based carbon fibers/biomass-derived hierarchical porous carbon for high-performance lithium-sulfur battery free-standing cathodes

Developing high-performance lithium-sulfur batteries has become an important strategy to achieve sustainable development. In this study, a novel and high-performance stand-alone cathode material, containing Ni-plated viscose-based carbon fiber (VBCF/Ni) and hierarchical porous carbon (HPC), was prepared. The conductivity, adsorption and catalytic effect of the VBCF substrate, on the Li2S/LiPSs, were improved after Ni-plating. HPC, containing micro- and mesopores, was obtained by carbonizing edible sweet potato flour and served as a direct host for sulfur (HPC@S). The large specific surface area (386.8 m2 g−1) and pore volume (0.4556 cm3 g−1) of HPC were suitable for achieving a good sulfur loading and LiPSs adsorption. Due to the synergistic effect of the polar metallic Ni and non-polar carbon groups, the performance of the VBCF/Ni/HPC@S cathode was significantly improved. The obtained cell showed a reversible capacity of 1206 mAh g−1 at 0.1 C, maintained 892.2 mAh g−1 after 200 cycles at a rate of 0.2 C, and showed a capacity retention rate of 82.6%.