N-doped 3D reduced graphene oxide supported C-encapsulated Co9S8/Co4S3 composites as anode for improved lithium storage

Carbon-coating nitrogen all-doped Co9S8/Co4S3 nanoparticles attached to reduced graphene oxide sheets (N-CS@C/G) was developed by an eco-friendly in situ methodology in this study. Glucose-derived carbon nano-wrapped layers and supported reduced graphene oxide were employed to develop a highly conductive network, whereas N dopants, Co9S8 and Co4S3 supplied additional electrochemical active sites for lithium-ion energy storage. The well-designed hetero-structured N-CS@C/G electrode with a specific surface area of 101.29 m2g−1 can contribute to notably improving the volume variation and raising electrical conductivity. Under the N-CS@C/G composites with the improved synergistic effect that served as anode, the cell exhibited progressive cycle stability of 662 mA h g−1 at 2 A g−1 when 600 cycles were completed, the high specific capacity of 1039.7 mA h g−1 at 0.05 A g−1, as well as prominent rate capability, outperforming the parallel comparison materials without the addition of glucose (N-CS) or reduced graphene oxide (N-CS@C). This study is likely to develop a distinctive avenue to produce quick and high-capacity metal sulfide anodes and boot high-performance lithium-ion batteries. •N-CS@C/G was produced with the use of a low temperature hydrothermal, freeze-drying and subsequent calcination method.•The electrode can be endowed with low Li+ diffusion impedance by glucose and urea in-situ developed carbon layer and N-doped.•Reduced graphene oxide prevents agglomeration, while providing the electronic conduction between CoxSy nanoparticles.•N-CS@C/G heterostructure is characterized by prominent rate capability, cycle performance and high specific capacity.