Luo Rui, Zheng Junchao, Zhou Zhiwei, Li Jingyi, Li Yunjiao, He Zhenjiang
School of Metallurgy and Environment, Central South University, Changsha, Hunan410083, China.
National Engineering Laboratory for High Efficiency Recovery of Refractory Nonferrous Metals, Central South University, Changsha410083, China.
ACS Appl Mater Interfaces. 2022 Oct 26;14(42):47863-47871. doi: 10.1021/acsami.2c12894. Epub 2022 Oct 14.
P2-type NaMnO with a stable structure and an open framework can provide numerous channels for fast Na de/intercalation, for which it is considered to be advantageous in application of the cathode material for Na-ion batteries. However, the complex phase transition occurring during cycling and the lattice distortion triggered by the Jahn-Teller effect severely restrict its development. Herein, the modified NaMnO with Cu or Fe single-element doping as well as Cu and Fe double-element doping was synthesized by the sol-gel method, and the effects of doping on the crystal structure and electrochemical performances of NaMnO were studied. It was demonstrated that the phase of the material did not change after the introduction of Cu and Fe elements, and the cycling stability and rate performance were greatly improved by Cu and Fe double-doping owing to their synergistic effect. The NaMnFeCuO (NMFCO) cathode delivers discharge specific capacities of 110.5 mA h g at 5 C and 91.8 mA h g at 10 C and exhibits the high-capacity retention of 94.35% at 1 C and 90.68% at 5 C after 100 cycles. Overall, this study offers a guiding direction for accelerating the modification of P2-type NaMnO as a cathode active material for high performance Na-ion batteries.
具有稳定结构和开放框架的P2型NaMnO可为快速的钠嵌入/脱嵌提供众多通道，因此被认为在钠离子电池正极材料的应用中具有优势。然而，循环过程中发生的复杂相变以及由 Jahn-Teller 效应引发的晶格畸变严重限制了其发展。在此，通过溶胶-凝胶法合成了 Cu 或 Fe 单元素掺杂以及 Cu 和 Fe 双元素掺杂的改性 NaMnO，并研究了掺杂对 NaMnO 晶体结构和电化学性能的影响。结果表明，引入 Cu 和 Fe 元素后材料的相没有变化，并且由于 Cu 和 Fe 的协同效应，双掺杂极大地提高了循环稳定性和倍率性能。NaMnFeCuO (NMFCO) 正极在 5 C 时的放电比容量为 110.5 mA h g，在 10 C 时为 91.8 mA h g，并且在 1 C 下 100 次循环后具有 94.35% 的高容量保持率，在 5 C 下为 90.68%。总体而言，本研究为加速将 P2 型 NaMnO 改性为高性能钠离子电池的正极活性材料提供了指导方向。
