Amorphous iron phosphate: potential host for various charge carrier ions

作者：Vinod Mathew, Sungjin Kim, Jungwon Kang, Jihyeon Gim, Jinju Song, Joseph Paul Baboo, Wan-Geun Park, Docheon Ahn, Jun-Hee Han, Lin Gu, Yuesheng Wang, Yong‐Sheng Hu, Yang‐Kook Sun, Jaekook Kim · 发表于：NPG Asia Materials · 年份：2014 · DOI：10.1038/am.2014.98 · 被引用次数：265 · 研究领域：Advanced battery technologies research、Advancements in Battery Materials、Supercapacitor Materials and Fabrication

In response to the ever-increasing global demand for viable energy-storage systems, sodium and potassium batteries appear to be promising alternatives to lithium ion batteries because of the abundance, low cost and environmental benignity of sodium/potassium. Electrical energy storage via ion-intercalation reactions in crystalline electrodes is critically dependent on the sizes of the guest ions. Herein, we report on the use of a porous amorphous iron phosphate synthesized using ambient temperature strategies as a potential host that stores electrical energy through the feasible insertion of mono-/di-/tri-valent ions. A combination of ex situ studies reveals the existence of a reversible amorphous-to-crystalline transition in this versatile electrode during electrochemical reactions with monovalent sodium, potassium and lithium. This reconstitutive reaction contributes to realizing specific capacities of 179 and 156 mAhg−1 versus sodium and potassium at current densities of 10 and 5 mAg−1, respectively. This finding facilitates the feasible development of several amorphous electrodes with similar phase behavior for energy-storage applications. Cation redox hosts are realized that undergo crystalline–amorphous transitions with large cations on electrochemical or chemical reactions. Jaekook Kim from Chonnam National University and co-workers based in South Korea and China show that porous amorphous iron phosphate can act as a host for various charge-carrier ions with large ioni...