Comparative study of approaches to achieve improved cyclability and high capacity in a silicon suboxide film anode for lithium-ion batteries

To simultaneously achieve high capacity and good cyclability for silicon suboxide (SiOx) as a Li-ion battery anode material, we compared two different approaches under the same volume change rate of SiOx during charge/discharge cycling: choosing a SiOx sample with appropriate x and restricting the available capacity in a sample with low x. Herein, the effect of capacity restriction in SiO0.17 on improving the cyclability was examined, by which the volume change of Li-Si alloy decreased. As a result, the SiO0.17 film electrode that was partially lithiated by cutting off the charging potential at 0.2 V vs. Li/Li+ exhibited good cyclability similar to the fully lithiated SiO0.68; however, the energy density of the former became eventually lower than that of the latter. These results showthat choosing a SiOx sample with an appropriate x was a better alternative than restricting the capacity of a low x sample. (C) 2017 Elsevier Ltd. All rights reserved.