Lithium ion batteries (LIBs) have been wide applied in portable electronics, electric vehicles, etc. Meanwhile, due to the limited resources of lithium and their uneven distributions, as well as the shortage of cobalt resources, LIBs can hardly meet the demand of large-scale applications. Due to the similarity between sodium and lithium and the rich abundance of sodium, sodium ion batteries (NIBs) become promising alternative However, the application of NIBs is limited by lacking of suitable and cheap cathode materials. The main reason is that since sodium ion has a larger ion radius than lithium ion, it is relatively difficult for sodium ion to desert/insert from/into the positive electrode material, which requires a more stable crystal skeleton and larger ion diffusion channels.
Recently, Prof. Tang and his team successfully developed a new mixed polyanionic compound, Na2Fe(C2O4)SO4·H2O, as a cathode for NIBs. This cathode exhibits excellent electrochemical reversibility and stability. Its electrochemical mechanism was further demonstrated to be originated from the redox of Fe2+/Fe3+ through in-situ synchrotron X-ray measurements and DFT calculations. Simulation also revealed that the high stability is owing to the large size of sodium ion migration channels and its rigid three-dimensional framework. Relevant researches have been published in Angew. Chem. Int. Ed. (2020, 59, 740), and wide reported by media.
New Energy Network and other media reports on the research results
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