Review—Practical Issues and Future Perspective for Na-Ion Batteries

Research on electrochemical Na intercalation in battery system has been reported since the early 1980s but Na-ion batteries are not commercialized so far though studies on Li-ion batteries have been reported since the late 1970s and the practical batteries have been extensively utilized for portable device applications in the world since 1991. Now, targeted application of research and development for rechargeable batteries has changed toward realization of the sustainable energy society. With the change in social situation and development of the battery technology, studies on Na-ion batteries have been attracted significant interests since 2010. Although research interests of the electrode materials for Na-ion batteries are evoked in many researchers, advantages, disadvantages, and issues are not fully discussed for realizing the commercialization of Na-ion batteries. In this article, practical issues and perspective are reviewed on the basis of mainly our experimental experiences, know-how, and results, and the future direction is proposed to overcome the issues and to challenge the advanced performance.