9-3-1 Development of All Solid Lithium-ion Batteries with Metal Hydride Electrode

Abstract

Recently, metal hydrides have been studied as conversion-type negative electrode materials for lithium-ion battery. Magnesium hydride (MgH₂) known as hydrogen storage materials is one of promising electrode materials because of the high theoretical capacity, which is 2036 mAh/g and five times larger than that of conventional graphite electrode. During the reaction with Li ions, MgH₂ is converted to Mg and LiH. On the analogy on MgH₂, it is expected that other hydrides also work as electrode materials. However, there are few reports about other hydrides currently. In this work, the electrochemical properties of metal hydrides, such as MgH₂, TiH₂, CaH₂ and VHx, are systematically investigated. From the experimental results, the correlation between thermodynamic and electrochemical properties is clearly found except for CaH₂. In the case of CaH₂, an unexpected side reaction possibly proceeds.