LIBs can hardly meet the urgent demand of large-scale energy storage due to the limited lithium and cobalt resources and their uneven distributions. Until now, the anode and electrolytes for potassium ion batteries (KIBs) are relatively mature, while the development of corresponding cathodes is slow. Since the size of K+ (1.38 Å) is much larger than Li+ (0.76 Å), large migration channels and stable crystal structures are essential for K ion migration, which raises a great challenge to develop suitable cathodes.

In this situation, Tang’s team has developed a stable cathode, KFeC2O4F, for potassium storage. Thanks to the large channels in the three-dimensional open framework, it exhibits a small volume change of 7.6%, comparable to LiFePO4 cathode (~ 7.8%), during K-ion desertion. Owing to its intrinsic Fe2+/Fe3+ redox mechanism, rigid 3D [FeC2O4F] framework and three open channels, the KFeC2O4F cathode yielded a reversible discharge capacity of ~112 mAh g−1 at 0.2 A g−1 and kept high capacity retention of 94% over 2000 cycles, indicating the feasibility of KFeC2O4F as a promising KIB cathode for sustainable large-scale energy storage applications. Relevant studies is published on Nat. Commun. (2020, 11, 1225), and wide reported by media.

Science Network and other media reports on the research results

The links to the news:

http://xincailiao.com/news/news_detail.aspx?id=561635 

http://news.sciencenet.cn/htmlnews/2020/3/436940.shtm