Repeated formation and destruction of the SEI layer consumes lithium and electrolyte, resulting in the decay of battery performance. The morphologies of anodes before and after 300 cycles were observed via SEM to measure the volume expansion (Fig. , Fig. and Fig. ). After 300 cycles, for Si-SiOx@C and Si-SiOx@C-2.5, cracks are obvious on the surface and delamination from the current collector occurred. Si-SiOx@C-5 has no obvious cracks but significant volume expansion. Based on the cross-section images before and after 300 cycles, the estimated volume expansion rates were listed in Table . The volume expansion of Si-SiOx@C-1.25 after 300 cycles is only 71.4%, which is highly lower than Si-SiOx@C without CNT. Therefore, the introduced CNT nano-skeleton structure could significantly reduce the negative effects of volume expansion and create more conductive pathways, thus improving cycling performance. Cycling performances under 0.5 A•g -1 (Fig. ) and 1 A•g -1 (Fig. ) were investigated. The performance decay under higher current densities shows more intense tendency, while Si-SiOx@C-1.25 is still the optimal one. Si-SiOx@C-1.25 delivers the discharge capacities of 569 mAh•g -1 at 0.5 A•g -1 after 100 cycles and 292.5 mAh•g -1 at 1 A•g -1 after 300 cycles.