Impact of Transition Metal Layer Vacancy on the Structure and Performance of P2 Type Layered Sodium Cathode Material

• Published in: Nano-micro letters 2024-12, Vol.16 (1), p.239-19, Article 239
• Main Authors: Zhanadilov, Orynbay, Baiju, Sourav, Voronina, Natalia, Yu, Jun Ho, Kim, A-Yeon, Jung, Hun-Gi, Ihm, Kyuwook, Guillon, Olivier, Kaghazchi, Payam, Myung, Seung-Taek
• Format: Article
• Language: English
• Subjects: Cathode; Cathodes; Density; Electrode materials; Electrons; Energy storage; Engineering; Layered oxide; Lithium; Mass spectrometry; Na-ion batteries; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Oxidation; Oxygen; Oxygen evolution; Phase transitions; Scientific imaging; Sodium; Sodium battery; Sodium-ion batteries; Structural stability; Transition metals; Vacancy; X ray absorption
• ISSN: 2311-6706; 2150-5551; 2150-5551
• DOI: 10.1007/s40820-024-01439-9

Highlights Vacancy in the transition metal layer of sodium cathode material induces the formation lone-pair electrons in the O 2 p orbital. Material delivers more capacity from the oxygen redox validated by density functional calculation. Widened dominance of the OP4 phase without releasing O 2 gas. This study explores the impact of introducing vacancy in the transition metal layer of rationally designed Na 0.6 [Ni 0.3 Ru 0.3 Mn 0.4 ]O 2 (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 Na 0.7 [Ni 0.2 V Ni0.1 Ru 0.3 Mn 0.4 ]O 2 (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 2 p 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 O 2 gas. These findings offer valuable insights for the design of advanced high-capacity cathode materials with improved performance and sustainability in sodium-ion batteries.