Structure modulation strategy for suppressing high voltage P3-O1 phase transition of O3-NaMn0.5Ni0.5O2 layered cathode

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-03, Vol.431, p.133454, Article 133454
• Main Authors: Huang, Qun, Feng, Yiming, Wang, Lei, Qi, Shuo, He, Pingge, Ji, Xiaobo, Liang, Chaoping, Chen, Shuangqiang, Zhou, Liangjun, Wei, Weifeng
• Format: Article
• Language: English
• Subjects: Electrochemical properties; Layered oxide cathode; Mg/Ti co-substitution; Structural stability; Structure modulation
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.133454

•The Mg/Ti co-doped O3-type NaMn0.45Ni0.45Mg0.05Ti0.05O2 has been successfully synthesized.•The formation energy and band gap of O3 phase has been reduced by Mg/Ti co-doping strategy.•The high-voltage detrimental P3-O1 phase transition has been inhibited by Mg/Ti co-doping.•The cycling stability and rate capability of O3 phase have been enhanced by Mg/Ti co-doping. Layered O3-type NaMn0.5Ni0.5O2 has been widely investigated as cathode material for sodium-ion batteries (SIBs). However, it usually suffers from detrimental phase transformation upon high voltage (>4.1 V) and sluggish Na+ migration kinetics, leading to rapid capacity decay and limited rate capability. Herein, guided by the first principles calculations, a structure modulation strategy to construct mechanically robust transition metal oxides (TMO2) layers for O3-NaMn0.5Ni0.5O2 is realized through Mg/Ti co-substitution. After Mg/Ti co-substitution, the capability of the TMO2 layers framework of O3 phase has been significantly improved to go against and tolerant strains and distortions, and thus remarkably enhanced the electrochemical performance of O3 phase upon high voltage. The as-prepared O3-type NaMn0.45Ni0.45Mg0.05Ti0.05O2 exhibits an initial discharge capacity of 177.7 mAh g−1 at a current density of 0.1 C in a voltage range of 2.0–4.2 V, and the detrimental P3-O1 phase transition upon 4.0 V can be effectively suppressed as well as the Na+ diffusion kinetics is enhanced under high voltage, subsequently leading to improved high voltage cycling-stability and rate-capability.