3D Carbon Coating Enabled High-capacity and Stable Micro-sized Silicon Suboxide-graphite Blended Anodes for Practical Lithium-ion Batteries

Silicon oxide (SiOx) is a promising anode candidate of lithium-ion batteries (LIBs) owing to its extremely high specific capacity. However, the low initial Coulombic efficiency (ICE) and rapid capacity degradation of SiOx, triggered by the enormous volume variation upon repeated (de)lithiation, gravely hinder its practical use. Herein, two mass-produced micro-sized SiOx@C composites with obviously different morphologies for commercial LIBs are reported. Particularly, the SiOx-graphite blended anode (SiOx@3D-G-Gr) based on SiOx wrapped by three-dimensional (3D) carbon layers (SiOx@3D-G) exhibits a capacity of 519 mAh g(-1), an ICE of 90.0 % and a capacity retention of 83.4 % at 0.2 C over 100 cycles. which is far exceeding its counterpart SiOx@C-H-Gr (65.7 %). The obtained impressive properties of SiOx@3D-G originate from the critical contribution of 3D carbon layers, which serves as the effective stress buffer and protective layer as well as the strong networks for electron/Li+ transport. Accordingly, the full-cell based on SiOx@3D-G-Gr anode and commercial LiCoO2 cathode delivers a capacity of 803 mAh and an excellent capacity retention of 95.6 % (616 mAh, 96.6 % for graphite, respectively) at 1 C over 100 cycles with a stabilized CE of nearly 100 %. The micro-sized SiOx@3D-G showing a promising prospect in the commercial-grade anodes in LIBs.

Automated summary

This article reports on the study of two mass-produced micro-sized SiOx@C composites with different morphologies for commercial lithium-ion batteries. The SiOx@3D-G-Gr composite, based on SiOx wrapped by three-dimensional carbon layers, exhibits high capacity and excellent battery performance over 100 cycles, outperforming its counterpart SiOx@C-H-Gr. This highlights the critical role of three-dimensional graphene in improving battery performance.