Optimization prelithiation current of silicon-oxygen anode for high specific energy li-ion cells

Abstract

In order to improve the cycling stability of silicon‑oxygen anode for high specific energy Li-ion cells, the effect of prelithiation current on the interfacial film of silicon‑oxygen anode is investigated in this paper. AFM and XPS results showed that the cell performance of 0.05C prelithiation was optimal, the negative electrode solid electrolyte interphase (SEI) film formation is more complete, the surface is uniform and flat, and the cell impedance is lower. The 350 Wh kg−1 full cells of high nickel‑silicon carbon system are fabricated to test the effect of prelithiation at the different rates (0.02C, 0.05C, 0.08C, 0.1C) on the electrochemical performances of the cell. The results show that the cell with 0.05C prelithiation exhibit the best electrochemical performances. After 300 cycles at 1C, the capacity retention of 0.05C prelithium cells is still 86.5 %, which is 1.8 %, 3.5 %, and 3.7 % higher than that of prelithium cells using 0.02C, 0.08C, and 0.1C, respectively. Seemingly, suitable prelithiation current can optimize the film-forming properties of SEI film and improve the cycling stability of silicon‑oxygen high specific energy Li-ion cells.