Enveloping SiOx in N-doped carbon for durable lithium storage via an eco-friendly solvent-free approach

Silicon oxides, SiOx, have aroused significant interests as high-capacity lithium-ion battery anode materials. To address the conductivity and volume fluctuation issues of SiO(x)for practical applications, herein, we develop a novel eco-friendly, solvent-free, flammable gas-free approach to envelop SiO(x)submicron particles in N-doped carbon (denoted as SiOx@NC). The carbon encapsulation not only improves the electrical conductivity but also buffers the volume variation of SiOx, resulting in boosted lithium storage performances. Specifically, the as-prepared SiOx@NC affords high reversible capacity (774 mA h g(-1)), ideal rate capability, and long-term durability (112% capacity retention over 500 cycles). It is expected that the solvent-free, flammable gas-free method we developed here can be generally applied to other high-capacity anode materials, such as Si, Sn, and Sb.