Lithium Intercalation from Aqueous Solutions

Lithium can be intercalated into a wide variety of materials using nonaqueous electrochemical cells. The use of aqueous methods is less common because of the reactivity of many lithium intercalation compounds with water. Here we show that lithium can be intercalated into host compounds from aqueous LiOH solution, provided the chemical potential of the intercalated l ithium is sufficiently lower than the chemical potential of l ithium in l ithium metal. Us ing L iMn~O ~ as the host, we fo rmed L i2Mn204 by intercalating Li f rom L iOH solution in an aqueous cell. This method may prove to be an economica l wayof preparing l ithium transition metal oxides with high l ithium contents for l ithium-ion cell cathodes. Lithium-ion cells now represent the state-of-the-art in small-size rechargeable batteries for consumer electronic devices. The common choices for cathode materials in these cells are LiCoO2, LiNiO2, and the spinel, LiMn204. LiCoO2/ carbon 1cells are now in commercial production and have about twice the energy density of nickel-cadmium and nickel metal-hydride cells. Furthermore, the cells have an average discharge voltage of about 3.8 V, which allows a