Combination of 3D conductive network and all-fluorinated electrolyte for high-performance microsized silicon anode

Abstract

Silicon-based materials are promising candidates for anodes of rechargeable lithium-ion batteries due to their high theoretical capacities and natural abundance. However, the large volume changes during discharge-charge processes, results in structural degradation and serious specific capacity decay. Compared to the over-emphasized efforts on the nanostructured Si-based materials, the understanding and application of microsized Si electrodes are significantly lacking. In this work, for the first time, we demonstrate that combination of three-dimension (3D) conductive network and all-fluorinated electrolyte can significantly improve the cycling stability of microsized Si electrode. The galvanostatic discharge/charge test showed that the microsized Si electrode with 3D conductive network delivered a reversible capacity of 2084 mAh g−1 at 1000 ​mA ​g−1 after 200 cycles in all-fluorinated electrolyte. Further analysis using X-ray photoelectron spectroscopy, transmission electron microscopy and cyclic voltammetry demonstrated that its excellent performances are attributed to enhanced electron conductivity and forming a robust, uniform and LiF-dominated solid-electrolyte interphase layer.