To create high-performance electrochemical energy conversion devices, our laboratory covers fundamental studies as well as the foundation for practical applications. From the viewpoint of materials chemistry and electrochemistry, we create novel battery materials, which are based on the understanding of physicochemical phenomena, in order to improve the performance of power storage devices. In particular, we focus on high-power lithium ion batteries for use in hybrid vehicles, which will reduce environmental burdens. In addition, we fundamentally study on the design of electrode reactions for innovative energy conversion devices with high environmental compatibility for next generation.