A 3.8-V earth-abundant sodium battery electrode

Rechargeable lithium batteries have ushered the wireless revolution over last two decades and are now matured to enable green automobiles. However, the growing concern on scarcity and large-scale applications of lithium resources have steered effort to realize sustainable sodium-ion batteries, ​Na and ​Fe being abundant and low-cost charge carrier and redox centre, respectively. However, their performance is limited owing to low operating voltage and sluggish kinetics. Here we report a hitherto-unknown material with entirely new composition and structure with the first alluaudite-type sulphate framework, Na2Fe2(SO4)3, registering the highest-ever Fe3+/Fe2+ redox potential at 3.8 V (versus ​Na, and hence 4.1 V versus ​Li) along with fast rate kinetics. Rare-metal-free Na-ion rechargeable battery system compatible with the present Li-ion battery is now in realistic scope without sacrificing high energy density and high power, and paves way for discovery of new earth-abundant sustainable cathodes for large-scale batteries.UTokyo Research掲載「新物質発見で電池のレアメタル使用ゼロに」 URI: http://www.u-tokyo.ac.jp/ja/utokyo-research/research-news/materials-discovery-for-earth-abundant-battery/UTokyo Research "Materials discovery for earth-abundant battery" URI: http://www.u-tokyo.ac.jp/en/utokyo-research/research-news/materials-discovery-for-earth-abundant-battery