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.
