Operando NMR and XRD study of chemically synthesized LiC_x oxidation in a dry room environment

We test the stability of pre-lithiated graphite anodes for Li-ion batteries in a dry room battery processing room. The reaction between LiC_x and laboratory air was followed using operando NMR and x-ray diffraction, as these methods are sensitive to change in Li stoichiometry in graphite. There is minimal reactivity between LiC₆ and N₂, CO₂ or O₂; however, LiC₆ reacts with moisture to form lithium (hydr)oxide. The reaction rate follows zero-order kinetics with respects to intercalated lithium suggesting that lithium transport through the graphite is fast. The reaction occurs by sequential formation of higher stages–LiC₁₂, then LiC₁₈, and then LiC₂₄–as the hydrolysis proceeds to the formation of Li_xOH_y and graphite end products. Slowing down the formation rate of the Li_xOH_y passivation layer stabilizes of the higher stages.