Prelithiation of Lithium Peroxide for Silicon Anode: Achieving a High Activation Rate.

The use of lithium peroxide (LiO) as a cost-effective low-weight prelithiation cathode additive was successfully demonstrated. Through a series of studies on the chemical stability of LiO and the activation process of LiO on the cathode, we revealed that LiO is more compatible with conventional electrolyte and cathode laminate slurry than lithium oxide. Due to the significantly smaller size of commercial LiO, it can be used directly as a cathode additive. Moreover, the activation of LiO on the cathode leads to the impedance growth of the cathode possibly resulting from the release of dioxygen and evacuation of LiO inside the cathode. With the introduction of a new LiO spread-coating technique on the cathode, the capacity loss was suppressed. Si||NMC full cells using LiO spread-coated cathode demonstrated a highly promising activation rate of LiO and significantly enhanced specific capacity and cycling stability compared to the uncoated full cells.