本研究探讨了在合理设计的Na0.6[Ni0.3Ru0.3Mn0.4]O2(NRM)正极材料的过渡金属层中引入空位的影响。Ru的掺入,Ni,空位增强了广泛循环过程中的结构稳定性,增加工作电压,并诱导容量增加,同时还激活氧氧化还原,分别,在Na0.7[Ni0.2VNi0.1Ru0.3Mn0.4]O2(V-NRM)化合物中。各种分析技术,包括透射电子显微镜,X射线吸收近边缘光谱,操作X射线衍射,和操作差分电化学质谱法用于评估平均氧化态和结构畸变的变化。结果表明,V-NRM表现出比NRM更高的容量,并且在100次循环后保持81%的中等容量保持率。此外,在O2p轨道中形成额外的孤对电子使V-NRM能够利用通过密度泛函计算验证的氧氧化还原的更多容量,导致OP4相的优势扩大,而不会释放O2气体。这些发现为设计具有改善钠离子电池性能和可持续性的先进高容量阴极材料提供了宝贵的见解。
This study explores the impact of introducing vacancy in the transition metal layer of rationally designed Na0.6[Ni0.3Ru0.3Mn0.4]O2 (NRM) cathode material. The incorporation of Ru, Ni, and vacancy enhances the structural stability during extensive cycling, increases the operation voltage, and induces a capacity increase while also activating oxygen redox, respectively, in Na0.7[Ni0.2VNi0.1Ru0.3Mn0.4]O2 (V-NRM) compound. Various analytical techniques including transmission electron microscopy, X-ray absorption near edge spectroscopy, operando X-ray diffraction, and operando differential electrochemical mass spectrometry are employed to assess changes in the average oxidation states and structural distortions. The results demonstrate that V-NRM exhibits higher capacity than NRM and maintains a moderate capacity retention of 81% after 100 cycles. Furthermore, the formation of additional lone-pair electrons in the O 2p orbital enables V-NRM to utilize more capacity from the oxygen redox validated by density functional calculation, leading to a widened dominance of the OP4 phase without releasing O2 gas. These findings offer valuable insights for the design of advanced high-capacity cathode materials with improved performance and sustainability in sodium-ion batteries.