Co3S4 ultrathin nanosheets entangled on N-doped amorphous carbon coated carbon nanotubes with C S bonding for high performance Li-ion batteries

Abstract Cobalt sulfides are promising electrode materials for lithium ion batteries due to its high theoretical capacity. However, the disadvantages of low conductivity, poor cyclability combined with the large structural variation severely hinder its practical application. In this work, Co3S4 nanosheets on N doped amorphous carbon coated carbon nanotubes (CNTs@NC@Co3S4) are designed and fabricated, where the carbon nanotubes penetrate through Co3S4 ultrathin nanosheets and form conductive networks. The obtained CNTs@NC@Co3S4 effectively facilitates the electron and Li-ion transfer across the interface, prevents the aggregation of the nanosheets and provides more spaces for buffering the volume change, enabling the excellent electrochemical performance as anode for lithium ion batteries. The CNTs@NC@Co3S4 delivers specific capacity of 914 mAh g−1 after 100 cycles at 100 mA g−1 and 311 mAh g−1 after 500 cycles at 5000 mA g−1. The proposed strategy for constructing metal sulfides/carbon hybrids with chemical bonding provides new insights in developing the new electrode materials for high performance.