Enhanced electrochemical performance of sodium cathode materials with partial substitution of Zr

Status and prospects of O3-type layered oxide cathodes for Na-ion batteries: stability, reversibility, and reaction mechanism

“…NiO [36] ; (c) In-situ XRD results of NaNi0.5Mn0.5O2 [36] ; (d) Electrochemical performance changes of NaNi0.5Mn0.5O2 after Al doping [37] ; (e) In situ XRD patterns of NaNi0.5Mn0.5O2 before and after Mg/Ti co doping [48] ; (f) Changes in crystal interlayer spacing, cycling stability, and air stability of NaNi0.5Mn0.5O2 after Cu/Ti co-doping [46] . 解晨鹏等: 钠离子电池 O3 型层状氧化物正极的现状与展望：稳定性、可逆性及其反应机理 材料增加了 42%，在 480 mA/g 的高电流密度下，依 旧保有 90 mAh/g 的可逆比容量(图 4d) [37] 。Zr [38] ， Sb [39] ，Ti [40] ，Zn [41] 和 Sn [42] 等元素也具有类似作用。 Al 等无电化学活性的元素掺杂可有效提高 O3-NaNi0.5Mn0.5O2 的稳定性和倍率性能，但也不可避免 地降低了材料的比容量， 而一些具有电化学活性的元 素(Co [43] ，Cu [44] 和 Cr [45] )掺入材料，在提高稳定性 的同时，也能弥补材料容量下降的劣势。例如，Co 作 为掺杂元素引入正极材料， 除了稳定结构和改善倍率 性能之外，Co 3+ /Co 4+ 氧化还原对也会参与电荷补偿， 提供一定的比容量 [43] 。 鉴于单一的元素掺杂很难完全解决 O3-NaNi0.5Mn0.5O2 的诸多问题，目前的研究倾向于使用 多种元素进行共掺杂。例如，Yao [46] 等通过引入具有 更强电负性的…”

High-Performance Zr-Doped P3-Type Na0.67Ni0.33Mn0.67O2 Cathode for Na-Ion Battery Applications

“…Here, in our work, we systematically investigated Zr 4+ doping in the redox-inactive Mn site of P3-type Na 0.67 Ni 0.33 Mn 0.67 O 2 . As the ionic radius of Zr 4+ is larger than that of Mn 4+ , lattice expansion-associated positive changes in electrochemical performance, such as improved cycling stability and a rate capability similar to that observed in Zr doping in Li-ion cathodes, may be expected [42][43][44][45][46][47].…”