Encapsulating ultrafine cobalt sulfides into multichannel carbon nanofibers for superior Li-ion energy storage

Developing high-capacity anode materials based on metal sulfides is of great importance for building advanced lithium-ion batteries (LIBs). Herein, we demonstrate rational encapsulation of cobalt sulfide (CoSx) nanoparticles into multichannel carbon nanofibers (CoSx/MCF) with substantially improved Li+ reactivity and durability. The unique multichannel and conductive carbon scaffold not only affords boosted electron/Li + transportation pathways for fast redox reaction with CoSx, but also stabilizes the electrode structure by buffering the volume change of CoSx. Impressively, the CoSx/MCF composite could serve as flexible anodes to deliver a high reversible capacity of 737 mAh g+1 at 0.2 A g+1 after 100 cycles, superior rate capacity of 374 mAh g+1 at 5 A g+1, and excellent operating stability over 1000 cycles. Practical feasibility is also demonstrated by a full cell based on the high-capacity CoSx/MCF anode and Li[Ni0.8Co0.1Mn0.1]O2 cathode. The present study may provide insights for the facile synthesis of advanced anode materials for high-performance LIBs.

Automated summary

This study demonstrates the rational encapsulation of cobalt sulfide nanoparticles into carbon nanofibers, resulting in improved reactivity and durability as anode materials for lithium-ion batteries. The unique carbon scaffold enhances electron and Li+ transportation pathways and stabilizes the electrode structure, leading to high reversible and rate capacities, as well as excellent operating stability. These findings provide insights for the facile synthesis of advanced anode materials for high-performance lithium-ion batteries.