Cyanosol-enabled ultrafine alloy nanocrystals on graphene as a hybridization matrix for long-life and high-rate silicon anodes†

In silicon-based hybrid anodes, the uniform hybridization of silicon with conducting/buffering matrices is very critical in achieving desirable lithium storage performance. Herein, a cyanosol-derived electrostatic assembly and pyrolysis route has been developed to construct homogeneous silicon/metal/carbon (Si/M/C) ternary materials. Specifically, Si nanoparticles surrounded by ultrafine FeCo alloy are uniformly anchored on graphene (G), yielding a Si/FeCo/G nanohybrid. The incorporation of M/C dual matrices, with ultrafine alloy nanocrystals evenly distributed on graphene, into silicon could be responsible for the improved structural stability and charge-transport capability of the ternary anode. As a result, the Si/FeCo/G nanohybrid manifests good cycling stability (1426 mA h g⁻¹ after 100 cycles at 0.5 A g⁻¹) and high rate performance (1266 and 1118 mA h g⁻¹ at 5 and 10 A g⁻¹, respectively).