Although sodium is an abundant element that can be electrochemically and reversibly extracted from and inserted into layered materials, the resulting reversible capacity for storing energy remains low. A manganese–iron–sodium-based electrode is now shown to exhibit a reversible capacity of 190 mAh g−1 due to electrochemically active Fe3+/Fe4+ redox reactions.
- Naoaki Yabuuchi
- Masataka Kajiyama
- Shinichi Komaba
