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

The use of lithium peroxide (Li 2 O 2 ) as a cost-effective low-weight prelithiation cathode additive was successfully demonstrated. Through a series of studies on the chemical stability of Li 2 O 2 and the activation process of Li 2 O 2 on the cathode, we revealed that Li 2 O 2 is more compatible with conventional electrolyte and cathode laminate slurry than lithium oxide. Due to the significantly smaller size of commercial Li 2 O 2 , it can be used directly as a cathode additive. Moreover, the activation of Li 2 O 2 on the cathode leads to the impedance growth of the cathode possibly resulting from the release of dioxygen and evacuation of Li 2 O 2 inside the cathode. With the introduction of a new Li 2 O 2 spread-coating technique on the cathode, the capacity loss was suppressed. Si||NMC full cells using Li 2 O 2 spread-coated cathode demonstrated a highly promising activation rate of Li 2 O 2 and significantly enhanced specific capacity and cycling stability compared to the uncoated full cells.