Clarification of underneath capacity loss for O3-type Ni, co free layered cathodes at high voltage for sodium ion batteries

作     者：Dong Zhou De Ning Jun Wang Jiahua Liu Gaoyuan Zhang Yinguo Xiao Jiaxin Zheng Yongli Li Jie Li Xinzhi Liu Dong Zhou;De Ning;Jun Wang;Jiahua Liu;Gaoyuan Zhang;Yinguo Xiao;Jiaxin Zheng;Yongli Li;Jie Li;Xinzhi Liu

作者机构：Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275GuangdongChina School of Innovation and EntrepreneurshipSouthern University of Science and TechnologyShenzhen 518055GuangdongChina Centre for Photonics Information and Energy MaterialsShenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055GuangdongChina School of Advanced MaterialsPeking University Shenzhen Graduate SchoolShenzhen 518055GuangdongChina Institute for Clean Energy TechnologyNorth China Electric Power UniversityBeijing 102206China Department of EnergyPolitecnico di MilanoVia Lambruschini 4Milano 20156Italy Centre for Physical Mechanics and BiophysicsSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275GuangdongChina 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2023年第77卷第2期

页      面：479-486,I0012页

核心收录：

学科分类：081702[工学-化学工艺] 0808[工学-电气工程] 08[工学] 0817[工学-化学工程与技术] 

基　　金：financial support of the Guangdong Basic and Applied Basic Research Foundation(2019A1515110897 and 2019B1515120028) 

主　　题：Sodium ion batteries Layered oxide cathode Iron migration Operando X-ray absorption spectroscopy Neutron measurements 

摘      要：Earth abundant O3-type NaFe_(0.5)Mn_(0.5)O_(2)layered oxide is regarded as one of the most promising cathodes for sodium ion batteries due to its low cost and high energy ***,its poor structural stability and cycle life strongly impede the practical ***,the dynamic phase evolution as well as charge compensation mechanism of O3-type NaFe_(0.5)Mn_(0.5)O_(2)cathode during sodiation/desodiation are revealed by a systemic study with operando X-ray diffraction and X-ray absorption spectroscopy,high resolution neutron powder diffraction and neutron pair distribution *** layered structure experiences a phase transition of O3→P3→OP2→ramsdellite during the desodiation,and a new O3’phase is observed at the end of the discharge state(1.5 V).The density functional theory(DFT)calculations and nPDF results suggest that depletion of Na^(+)ions induces the movement of Fe into Na layer resulting the formation of an inert ramsdellite phase thus causing the loss of capacity and structural ***,the operando XAS clarified the voltage regions for active Mn^(3+)/Mn^(4+)and Fe^(3+)/Fe^(4+)redox *** work points out the universal underneath problem for Fe-based layered oxide cathodes when cycled at high voltage and highlights the importance to suppress Fe migration regarding the design of high energy O3-type cathodes for sodium ion batteries.