NC@BiS Nanospheres as High-Performance Anode Materials for Lithium-Ion Batteries.

BiS holds immense potential to be promoted as an anode material for lithium-ion batteries (LIBs), owing to the high theoretical gravimetric and volumetric capacities. However, the poor electrical conductivity and volume expansion during cycling hinder the practical applications of BiS. Therefore, through subsequent heat treatment, the nitrogen-doped carbon film was successfully loaded on the nanosphere BiS, which we call nitrogen-rich carbon layer-coated BiS (NC@BiS). Hence, the nanosphere BiS uniformly covered by a nitrogen-rich carbon layer was successfully coated on the BiS surface (NC@BiS) through post-treatment. Due to the effective interaction between glutathione and inorganic materials, dopamine hydrochloride molecules are introduced and polymerized on the surface of the spherical BiS structure and then converted into a nitrogen-rich carbon layer with an average thickness of 10.0 nm. The electrochemical tests reveal that the discharge specific capacities of BiS and NC@BiS reach 340.99 and 645.13 mAh/g after 300 cycles at 100 mA/g, respectively. Kinetic analysis shows that the contribution of pseudocapacitance behavior increases by about 10% after the nitrogen-rich carbon layer is coated. These results suggest the potential of NC@BiS as a high-performance anode material for LIBs; the stability can be enhanced by core-shell structures.