Synthesis of monodisperse SnCo nanoparticles in triethylene glycol and its carbon composites for advanced lithium-ion batteries

Abstract

The tin-based materials are one kind of the most promising high-capacity anode candidates for advanced Li-ion energy storage systems. However, they still face the problem of large volume expansion during charge–discharge processes, which causes rapid capacity decay and thus largely limit their serving life in practical application. In this work, ultra-fined SnCo alloy particles were successfully synthesized by a facile reduction of metal salts in triethylene glycol (TEG) solution, and then SnCo-anchored carbon composites were obtained through the calcination of SnCo-doped poly-(2-ethyl-2-oxazoline) (PEtOx) clusters. The microstructure, morphology, chemical composition and phase constitution are systematically analyzed. It is found that the as-prepared SnCo alloy particles exhibit a uniformly dispersed spherical morphology with a small average grain size of 20 nm and also a high reversible capacity of 459.1 mAh g[Formula: see text] after 100 cycles. More significantly, the SnCo/C nanocomposites present an excellent capacity retention ratio of 91.1% over 200 cycles at 100 mA g[Formula: see text] as well as good rate capability, suggesting that due to the accelerated electrons and Li[Formula: see text] transportation, the introduction of carbon matrix could significantly improve the stability of the active SnCo nanoparticles and inhibit the occurrence of their volume expansion during cycling.