Entropy‐Mediated Stable Structural Evolution of Prussian White Cathodes for Long‐Life Na‐Ion Batteries

作者：Yueyue He, Sören L. Dreyer, Yin‐Ying Ting, Yuan Ma, Yuan Ma, Yang Hu, Damian Goonetilleke, Yushu Tang, Thomas Diemant, Bei Zhou, Piotr M. Kowalski, Maximilian Fichtner, Horst Hahn, Jasmin Aghassi‐Hagmann, Torsten Brezesinski, Ben Breitung, Yanjiao Ma, Yanjiao Ma · 发表于：Angewandte Chemie International Edition · 年份：2023 · DOI：10.1002/anie.202315371 · 被引用次数：72 · 研究领域：Advancements in Battery Materials、Advanced battery technologies research、Electrocatalysts for Energy Conversion

Abstract The high‐entropy approach is applied to monoclinic Prussian White (PW) Na‐ion cathodes to address the issue of unfavorable multilevel phase transitions upon electrochemical cycling, leading to poor stability and capacity decay. A series of Mn‐based samples with up to six metal species sharing the N‐coordinated positions was synthesized. The material of composition Na1.65Mn0.4Fe0.12Ni0.12Cu0.12Co0.12Cd0.12[Fe(CN)6]0.92□0.08 ⋅ 1.09H2O was found to exhibit superior cyclability over medium/low‐entropy and conventional single‐metal PWs. We also report, to our knowledge for the first time, that a high‐symmetry crystal structure may be advantageous for high‐entropy PWs during battery operation. Computational comparisons of the formation enthalpy demonstrate that the compositionally less complex materials are prone to phase transitions, which negatively affect cycling performance. Based on data from complementary characterization techniques, an intrinsic mechanism for the stability improvement of the disordered PW structure upon Na+ insertion/extraction is proposed, namely the dual effect of suppression of phase transitions and mitigation of gas evolution.