Carbon coating hollow NiS nanoparticles anchored on Ti3C2 nanosheet as high-performance anode for lithium-ion batteries

Abstract

Exploring novel electrode materials is the key to developing attractive lithium-ion batteries (LIBs). Hence, we successfully synthesized NiS@C/Ti3C2 by in situ growth-sulfuration-pyrolysis strategies. As LIBs anode, its initial discharge capacity of NiS@C/Ti3C2 was 1509 mAh g−1 and its discharge capacity was 301.2 mAh g−1 at 1 A g−1. Most importantly, when the current density recovered to 0.03 A g−1 continuing 20 cycles and maintained excellent capacity of 864.6 mAh g−1. Notably, its capacity was 649.9 mAh g−1 after 700 cycles at 0.5 A g−1. Such extraordinary performances are mainly attributed to (1) carbon matrix can improve conductivity of composite material, effectively buffer volume expansion of material during cycles process, and prevent structure collapse. (2) the hollow structure produced by sulfuration, porous carbon matrix and the gaps among Ti3C2 nanosheets are conducive to the penetration of electrolytes. They provide abundant buffer space for volume expansion during Li+ embedding/stripping process, which effectively alleviates structure collapse and electrode crushing. (3) Ti3C2 nanosheets as high-conductive 2D substrate not only offer fast diffusion channels but also alleviate structure collapse of NiS@C. More importantly, this unique structure can alleviate restacking of Ti3C2 and provide affluent active sites, thus endowing material with improved electrical conductivity. Our work provides insightful insights into the design of transition metal sulfides (TMSs) anchored at Ti3C2 nanosheets as LIBs anode.