Li-metal-free prelithiation of Si-based negative electrodes for full Li-ion batteries

Abstract

Most of the high‐capacity positive‐electrode materials [for example, S, O2 (air), and MOx (M: V, Mn, Fe, etc.)] are Li‐deficient and require the use of a Li‐metal electrode or prelithiation. Herein, we report a novel electrolytic cell in which the Si electrode can be prelithiated in a well‐controlled manner from Li‐containing aqueous solution in a Li‐metal‐free way. MnOx/Si and S/Si Li‐ion full cells were assembled by using the prelithiated Si negative electrodes, which resulted in high specific energies of 349 and 732 Wh kg−1, respectively. The MnOx/Si full cell still retains 138 Wh kg−1 even at a high specific power of 1710 W kg−1. This is the first report of a whole process of making a full Li‐ion battery with both Li‐deficient electrodes without the use of Li metal as the Li source. This novel prelithiation process, with high controllability, no short circuiting, and an abundant Li source, is expected to contribute significantly to the development of safe, green, and powerful Li‐ion batteries.