Interconnected CoS2/NC-CNTs network as high-performance anode materials for lithium-ion batteries

Abstract

Cobalt disulfide (CoS2) has been considered a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity of 870 mA h g−1. However, its practical applications have been hampered by undesirable cycle life and rate performance due to the volume change and deterioration of electronic conductivity during the discharge-charge process. In this study, an interconnected CoS2/N-doped carbon/carbon nanotube (CoS2/NC-CNTs-700) network was successfully prepared to boost its lithium storage performance, in which small-size CoS2 nanoparticles were confined by N-doped carbon and uniformly decorated on the surface of CNTs. N-doped carbon can effectively accommodate the large volume expansion of CoS2 nanoparticles. Additionally, the 3D conductive nanostructure design offers adequate electrical/mass transport spacing. Benefiting from this, the CoS2/NC-CNTs-700 electrode demonstrates a long cycle life (a residual capacity of 719 mA h g−1 after 100 cycles at 0.2 A g−1) and outstanding rate performance (335 mA h g−1 at 5.0 A g−1). This study broadens the design and application of CoS2 and fosters the advances in battery anode research.