Fabrication of Thin Film Electrodes of LiMxMn_2-xO₄ (M = Ni, Co) for 5 Volt Lithium Batteries

By means of an electrostatic spray deposition technique, thin-films (0.5 μm thick) of LiM_xMn_2-xO₄ (M = Ni, Co) were fabricated on gold substrates. The prepared thin-films had a spinel-related structure. Cyclic voltammetry (CV) measurements were performed in a potential range of 3.4-5.5 V vs. Li/Li⁺. Both LiNi_xMn _2-xO₄ and LiCo_xMn_2-xO₄ exhibited reversible CV peaks at higher than 4.5 V. LiNi_xMn _2-xO₄ showed two peaks at 4.7 V, and those corresponded to the redox of Ni^{2+ /4+} in the spinel structure, while the redox of Mn^{3+ /4+} took place at 4 V. Similarly, LiCo_xMn _2-xO₄ displayed current responses at 5 V due to the redox of Co^{3+ /4+}.