Shinichi Komaba1 2 Kei Kubota1 2

1, Tokyo Univ of Science, Tokyo, , Japan
2, Kyoto University, Kyoto, , Japan

We have been studying electrode and electrolyte materials for Li-ion batteries. In the past 15 years, we have also studied the materials for Na-ion batteries [1,2]. As we described in the papers, yearly paper numbers of Na batteries have increased drastically in 2010s. Indeed, research and development of high-performance positive/negative electrode materials for Na-ion are conducted actively. Because of larger ionic size of sodium than lithium, much wider variety of materials chemistry attracts researchers’ interests as post Li-ion battery.
From 2013, we began to expand our research target to K-ion batteries, which is potentially expected to demonstrate higher-power and higher-voltage than Li-ion batteries, in spite of heavier and larger potassium atoms [3]. We study a variet of potassium insertion materials based on our experience of lithium and sodium ones, and their electrochemistry is examined and compared in corresponding non-aqueous electrolytes. We will talk about and introduce our recent progress on alkali-metal insertion materials for Na-ion and K-ion batteries and will discuss similarity and difference compared with Li-ion ones.
[1] N. Yabuuchi, S. Komaba, et al., Chem. Rev., 114, 11636 (2014).
[2] K. Kubota, S. Komaba et al., J. Electrochem. Soc., 162, A2538 (2015).
[3] X. Bie, S. Komaba et al, J. Mater. Chem. A, 5, 4325 (2017).