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

ABSTRACT

The use of lithium peroxide (Li2O2) as a cost-effective low-weight prelithiation cathode additive was successfully demonstrated. Through a series of studies on the chemical stability of Li2O2 and the activation process of Li2O2 on the cathode, we revealed that Li2O2 is more compatible with conventional electrolyte and cathode laminate slurry than lithium oxide. Due to the significantly smaller size of commercial Li2O2, it can be used directly as a cathode additive. Moreover, the activation of Li2O2 on the cathode leads to the impedance growth of the cathode possibly resulting from the release of dioxygen and evacuation of Li2O2 inside the cathode. With the introduction of a new Li2O2 spread-coating technique on the cathode, the capacity loss was suppressed. Si||NMC full cells using Li2O2 spread-coated cathode demonstrated a highly promising activation rate of Li2O2 and significantly enhanced specific capacity and cycling stability compared to the uncoated full cells.