南京师范大学周小四团队报道了，钾电池中高效磷酸基局域高浓度电解质的熵修复溶剂化结构策略。相关研究成果于2024年12月26日发表于国际顶尖学术期刊《德国应用化学》。

钾离子电池（PIBs）的安全性和循环稳定性与钾离子电解质密切相关。然而，由于钾离子的弱路易斯酸性，PIBs中的局部高浓度电解质容易发生过度的弱溶剂化。

该文中，研究人员提出了钾离子溶剂化结构的熵修复策略，并系统地设计了一种适度弱溶剂化的高熵局域高浓度电解质。修复后的电解质在Cu集电体表面上可以实现99.4%的平均稳定库仑效率。钾对称电池可以在0.5mA cm^-2的高电流密度和1mAh cm^-2的大沉积容量下稳定循环超过10000小时。

使用K_1.92Fe[Fe（CN）₆]_0.94·0.5H₂O作为阴极的钾金属袋电池，在电流密度为0.5A g^-1的2000次循环后保持87.5%的容量保持率。即使电流密度从0.1A g^-1增加十倍，电池仍保持其容量的67.1%。此外，由于引入了多种溶剂，以苝-3,4,9,10-四羧酸二酐为阴极的钾金属电池，可以保持94.0和77.3 mAh g^-1的可逆容量，并分别在20和40℃的环境温度下稳定运行。

附：英文原文

Title: Entropy-Repaired Solvation Structure Strategy for High-Efficiency Phosphate-Based Localized High-Concentration Electrolytes in Potassium Batteries

Author: Zeyu Yuan, Jiaying Liao, Lili Song, Anni Chen, Jiling Su, Jie Wang, Xiaosi Zhou

Issue&Volume: 2024-12-26

Abstract: The safety and cycling stability of potassium-ion batteries (PIBs) are deeply associated with potassium-ion electrolytes. However, due to the weak Lewis acidity of potassium ions, localized high-concentration electrolytes in PIBs are prone to excessive weak solvation. Herein, we propose an entropy repair strategy for the solvation structure of potassium ions and systematically design a moderately weakly solvated high-entropy localized high-concentration electrolyte. The repaired electrolyte can achieve an average stable Coulombic efficiency of 99.4% on the Cu collector surface. The potassium symmetric battery can be stably cycled for over 10000 h under a high current density of 0.5 mA cm2 and a large deposition capacity of 1 mAh cm2. The potassium metal pouch cell, using K1.92Fe[Fe(CN)6]0.940.5H2O as the cathode, maintains a capacity retention of 87.5% after 2000 cycles at a current density of 0.5 A g1. Even when the current density is increased tenfold from 0.1 A g1, the battery still retains 67.1% of its capacity. Additionally, due to the introduction of multiple solvents, the potassium metal battery with perylene-3,4,9,10-tetracarboxylic dianhydride as the cathode can maintain reversible capacities of 94.0 and 77.3 mAh g1 and operate stably at ambient temperatures of 20 and 40 ℃, respectively.

DOI: 10.1002/anie.202415923

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202415923