Improving the rate capability of a SiOx/graphite anode by adding LiNO3

SiOx/graphite anodes have attracted considerable attention in recent years due to their high specific capacity. Unfortunately, a thick solid-electrolyte-interface, which is produced by the decomposition of carbonate-based electrolytes, impedes the diffusion of lithium ions and significantly limits the rate performance of this interesting anode for practical applications. In this work, a LiNO3 additive was introduced during the preparation of an anode electrode paste. The results of SEM, ex and in situ XRD and XPS showed that LiNO3 decomposed into LiNxOy and Li3N, which deposited on the anode surface during the first discharge process. Due to the high ionic conductivity of LiNxOy and Li3N, the rate performance of the SiOx/graphite anode was significantly improved, showing a specific capacity nearly three times higher than that without the additive. In addition, the decomposition of the electrolyte during cycling was also suppressed by the LiNxOy and Li3N inorganic salts because of their low electronic conductivity and superior robustness. Our approach is facile and easy to scale up, which will be of great significance for the commercialization of SiOx/graphite anodes. [Display omitted] •LiNO3 is added to SiOx/graphite paste.•LiNO3 decomposes into LiNxOy and Li3N in the first cycle.•Rate performance of SiOx/graphite anode is significantly improved.