Hierarchical carbon nanofibers-based ternary conductive network built for improving electrochemical performance of SiOx@C anodes

Abstract

Si-based anodes are promising to be used in next-generation lithium ion batteries (LIBs), yet limited by low electrical conductivity and pulverization during cycling. The challenge is the simultaneous improvement of electrical conductivity and mechanical stability of the anodes under practical significance. Here, we constructed a ternary conductive 3D network based on hydroxyl-functionalized whisker-like carbon nanofibers (BH). We demonstrate that the hydrogen bond formed at the interactions between SiOx and the ternary conductive network can not only enhance electrode conductivity for the improved capacities and rate performance, but also increase interfacial adhesion strength for good structural stability. The ternary conductive 3D network constructed by BH, Super P, and SWCNTs at the optimal mass ratio of 2.95:7:0.05 enables the SiOx@C/graphite anode (10:90) a high initial discharge specific capacity (565 mAh g−1 at 0.1 C), high rate performance (320.1 mAh g−1 at 0.1 C), and outstanding cycling performance (381.9 mAh g−1 after 100 cycles at 0.2 C). Even the neat SiOx@C electrode with the optimized ternary conductive network delivers stable capacities of 1753.5 mAh g−1 at 0.5 C and 622.5 mAh g−1 at 10 C. The delicate design of 3D conductive networks in this work demonstrates great potential for the application of Si-based anodes in commercial LIBs with high energy densities.