Zhang Wei, Wu Yulun, Dai Yuhang, Xu Zhenming, He Liang, Li Zheng, Li Shihao, Chen Ruwei, Gao Xuan, Zong Wei, Guo Fei, Zhu Jiexin, Dong Haobo, Li Jianwei, Ye Chumei, Li Simin, Wu Feixiang, Zhang Zhian, He Guanjie, Lai Yanqing, Parkin Ivan P
School of Metallurgy and Environment, Engineering Research Center of the Ministry of Education for Advanced Battery Materials, Hunan Provincial Key Laboratory of Nonferrous Value-Added Metallurgy, Central South University Changsha 410083 P. R. China
Christopher Ingold Laboratory, Department of Chemistry, University College London London WC1H 0AJ UK
Chem Sci. 2023 Jul 27;14(32):8662-8671. doi: 10.1039/d3sc03095d. eCollection 2023 Aug 16.
High-voltage cathodes with high power and stable cyclability are needed for high-performance sodium-ion batteries. However, the low kinetics and inferior capacity retention from structural instability impede the development of Mn-rich phosphate cathodes. Here, we propose light-weight fluorine (F) doping strategy to decrease the energy gap to 0.22 eV from 1.52 eV and trigger a "Mn-locking" effect-to strengthen the adjacent chemical bonding around Mn as confirmed by density functional theory calculations, which ensure the optimized Mn ligand framework, suppressed Mn dissolution, improved structural stability and enhanced electronic conductivity. The combination of and techniques determine that the F dopant has no influence on the Na storage mechanisms. As a result, an outstanding rate performance up to 40C and an improved cycling stability (1000 cycles at 20C) are achieved. This work presents an effective and widely available light-weight anion doping strategy for high-performance polyanionic cathodes.
高性能钠离子电池需要具有高功率和稳定循环性能的高压阴极。然而，低动力学和结构不稳定性导致的容量保持率不佳阻碍了富锰磷酸盐阴极的发展。在此，我们提出轻量级氟（F）掺杂策略，将能隙从1.52 eV降至0.22 eV，并引发“锰锁定”效应——正如密度泛函理论计算所证实的，加强锰周围的相邻化学键，这确保了优化的锰配体框架、抑制了锰的溶解、提高了结构稳定性并增强了电子导电性。 技术的结合确定F掺杂剂对钠存储机制没有影响。结果，实现了高达40C的出色倍率性能和改善的循环稳定性（在20C下循环1000次）。这项工作为高性能聚阴离子阴极提出了一种有效且广泛适用的轻量级阴离子掺杂策略。
