Xu Xiaoqian, Chu Youqi, Mu Yongbiao, Wei Xianbin, Zhang Qing, Rao Haoyao, Gu Huicun, Pan Lyuming, Han Meisheng, Wang Yichun, Zeng Lin, Wei Lei
Shenzhen Key Laboratory of Advanced Energy Storage, Department of Mechanical and Energy Engineering, SUSTech Energy Institute for Carbon Neutrality, Southern University of Science and Technology, Shenzhen 518055, China.
Guangzhou Key Laboratory for Surface Chemistry of Energy Materials, New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
ACS Nano. 2025 Sep 9;19(35):31395-31406. doi: 10.1021/acsnano.5c05578. Epub 2025 Aug 27.
The typical P2-type NaNiMnO exhibits a high theoretical capacity for sodium-ion batteries (SIBs). However, its P2-O2 phase transition during deep charging causes severe structural degradation and capacity decay. In this work, we propose a site-selective doping strategy based on multielement synergy to suppress irreversible phase transitions. The alkali metal site doping by Sr doping as an interlayer pillar prevents cracks along the -plane and restrains interlaminar slip during deep desodiation. Y and Mo doping in transition metal layers stabilizes the transition metal bond and effectively prevents Na-O plate collapse during sodium deintercalation, dissipating strain accumulation and thereby inhibiting intergranular cracking. Additionally, Y/Mo doping activates additional Mn redox, effectively limits electron delocalization and charge order in transition metal layers, and creates a disordered sodium vacancy configuration, thus reducing the migration barrier of Na. Benefiting from this, the site-selectively doped P2-NaSrNiMnYMoO cathode exhibits excellent electrochemical performance, delivering a high reversible capacity of 90 mAh g at 200 C and maintaining 85.8% capacity retention after 2500 cycles at 20 C, significantly surpassing the pristine P2-NaNM cathode material. This work demonstrates the rational design of ultrastable layered cathode materials for sodium-ion batteries, contributing to the development of high-performance and long-life energy storage systems.
典型的P2型NaNiMnO对钠离子电池（SIBs）具有较高的理论容量。然而，其在深度充电过程中的P2 - O2相变会导致严重的结构退化和容量衰减。在这项工作中，我们提出了一种基于多元素协同作用的位点选择性掺杂策略来抑制不可逆相变。通过Sr掺杂作为层间支柱对碱金属位点进行掺杂可防止沿c平面出现裂纹，并在深度脱钠过程中抑制层间滑动。在过渡金属层中掺杂Y和Mo可稳定过渡金属键，并有效防止脱钠过程中Na - O板坍塌，消散应变积累，从而抑制晶间开裂。此外，Y/Mo掺杂激活了额外的Mn氧化还原反应，有效限制了过渡金属层中的电子离域和电荷有序性，并形成了无序的钠空位构型，从而降低了Na的迁移势垒。得益于此，位点选择性掺杂的P2 - NaSrNiMnYMoO正极表现出优异的电化学性能，在200℃时具有90 mAh g的高可逆容量，在20℃下2500次循环后容量保持率为85.8%，显著超过了原始的P2 - NaNM正极材料。这项工作展示了用于钠离子电池的超稳定层状正极材料的合理设计，为高性能和长寿命储能系统的发展做出了贡献。
