Dai Junyi, Tan Sha, Wang Lifeng, Ling Fangxin, Duan Fuqiang, Ma Mingze, Shao Yu, Rui Xianhong, Yao Yu, Hu Enyuan, Wu Xiaojun, Li Chunyang, Yu Yan
Hefei National Research Center for Physical Sciences at the Microscale, Department of Materials Science and Engineering, CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei 230026, Anhui, China.
Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States.
ACS Nano. 2023 Nov 14;17(21):20949-20961. doi: 10.1021/acsnano.3c02323. Epub 2023 Oct 31.
Prussian blue analogues (PBAs) used as sodium ion battery (SIB) cathodes are usually the focus of attention due to their three-dimensional open frame and high theoretical capacity. Nonetheless, the disadvantages of a low working voltage and inferior structural stability of PBAs prevent their further applications. Herein, we propose constructing the K(MnFeCoNiCu)[Fe(CN)] (HE-K-PBA) cathode by high-entropy and potassium incorporation strategy to simultaneously realize high working voltage and cycling stability. The reaction mechanism of metal cations in HE-K-PBA are revealed by synchrotron radiation X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and Raman spectra. We also investigate the entropy stabilization mechanism via finite element simulation, demonstrating that HE-K-PBA with small von Mises stress and weak structure strain can significantly mitigate the structural distortion. Benefit from the stable structure and everlasting K (de)intercalation, the HE-K-PBA delivers high output voltage (3.46 V), good reversible capacity (120.5 mAh g at 0.01 A g), and capacity retention of 90.4% after 1700 cycles at 1.0 A g. Moreover, the assembled full cell and all-solid-state batteries with a stable median voltage of 3.29 V over 3000 cycles further demonstrate the application prospects of the HE-K-PBA cathode.
用作钠离子电池（SIB）阴极的普鲁士蓝类似物（PBAs）通常因其三维开放框架和高理论容量而备受关注。尽管如此，PBAs工作电压低和结构稳定性差的缺点阻碍了它们的进一步应用。在此，我们提出通过高熵和钾掺入策略构建K（MnFeCoNiCu）[Fe（CN）]（HE-K-PBA）阴极，以同时实现高工作电压和循环稳定性。通过同步辐射X射线吸收光谱（XAS）、X射线光电子能谱（XPS）和拉曼光谱揭示了HE-K-PBA中金属阳离子的反应机制。我们还通过有限元模拟研究了熵稳定机制，证明具有小冯·米塞斯应力和弱结构应变的HE-K-PBA可以显著减轻结构畸变。得益于稳定的结构和持久的K（脱）嵌入，HE-K-PBA提供高输出电压（3.46 V）、良好的可逆容量（在0.01 A g下为120.5 mAh g），并且在1.0 A g下循环1700次后容量保持率为90.4%。此外，组装的全电池和全固态电池在3000次循环中具有3.29 V的稳定中值电压，进一步证明了HE-K-PBA阴极的应用前景。
