Ling Yuexia, Zhou Jiang, Guo Shan, Fu Hongwei, Zhou Yifan, Fang Guozhao, Wang Liangbing, Lu Bingan, Cao Xinxin, Liang Shuquan
School of Material Science and Engineering, Central South University, Changsha, Hunan 410083, China.
Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province, Central South University, Changsha, Hunan 410083, China.
ACS Appl Mater Interfaces. 2021 Dec 15;13(49):58665-58673. doi: 10.1021/acsami.1c18313. Epub 2021 Dec 2.
Layered sodium manganese oxides are promising low-cost and high-capacity cathode materials for commercialization of sodium-ion batteries (SIBs). P'2-type NaMnO with an orthorhombic structure has been considered as a significant candidate for SIBs. However, the Jahn-Teller distortion and undesired phase transitions will lead to poor structural stability and unsatisfactory cycling performance. Herein, a systematic investigation on partially copper-doped P'2-type NaCuMnO ( = 0, 0.05, 0.1, and 0.2) series as cathodes for SIBs reveals the relationship between doping concentrations and Na storage properties. With proper copper content, P'2 NaCuMnO exhibits a suppressed Jahn-Teller effect as well as relatively less phase transitions, which can deliver a high specific capacity of 222.7 mA h g at 10 mA g within 1.5-4.2 V, with a capacity retention of 76% at 1 A g after 300 cycles. The electrochemical mechanism is systematically investigated via in situ X-ray diffraction observations and density functional theory calculations, which provide fundamental guidelines for developing high-performance cathodes for SIBs.
层状钠锰氧化物是有望实现商业化的钠离子电池（SIB）低成本、高容量正极材料。具有正交结构的P'2型NaMnO被认为是SIB的重要候选材料。然而， Jahn-Teller畸变和不期望的相变会导致结构稳定性差和循环性能不理想。在此，对部分铜掺杂的P'2型NaCuMnO（ = 0、0.05、0.1和0.2）系列作为SIB正极进行了系统研究，揭示了掺杂浓度与钠存储性能之间的关系。在适当的铜含量下，P'2 NaCuMnO表现出抑制的Jahn-Teller效应以及相对较少的相变，在1.5 - 4.2 V范围内，10 mA g时可提供222.7 mA h g的高比容量，在1 A g下300次循环后容量保持率为76%。通过原位X射线衍射观察和密度泛函理论计算系统地研究了其电化学机理，为开发高性能SIB正极提供了基本指导。
