Identification of optimal composition with superior electrochemical properties along the zero Mn^(3+)line in Na_(0.75)(Mn-Al-Ni)O_(2)pseudo ternary system  

作　　者：Hari Narayanan Vasavan Manish Badole Samriddhi Saxena Velaga Srihari Asish Kumar Das Pratiksha Gami Neha Dagar Sonia Deswal Pradeep Kumar Himanshu Kumar Poswal Sunil Kumar 

机构地区：[1]Department of Metallurgical Engineering and Materials Science,Indian Institute of Technology Indore,Simrol 453552,India [2]High Pressure&Synchrotron Radiation Physics Division,Bhabha Atomic Research Centre,400085 Mumbai,India [3]School of Physical Sciences,Indian Institute of Technology Mandi,Himachal Pradesh 175005,India [4]Center for Electric Vehicle and Intelligent Transport Systems,Indian Institute of Technology Indore,Simrol 453552,India

出　　处：《Journal of Energy Chemistry》2024年第9期206-216,共11页能源化学（英文版）

基　　金：the Science and Engineering Research Board(SERB),Govt.of India,for the financial support(grant number:CRG/2021/005548).

摘　　要：Biphasic layered oxide cathodes,known for their superior electrochemical performance,are prime candidates for commercializing in Na-ion batteries.Herein,we unveil a series of P3/P2 monophasic and biphasic Al-substituted Na_(3/4)Mn_(5-x/8)Al_(2x/8)Ni_(3-x/8)O_(2)layered oxide cathodes that lie along the‘zero Mn^(3+)line’in the Na_(3/4)(Mn-Al-Ni)O_(2)pseudo-ternary system.The structural analysis showed a larger Na^(+)conduction bottleneck area in both P3 and P2 structures with a higher Al3+content,which enhanced their rate performance.In each composition,the P3/P2 biphasic compound with nearly equal fractions of P3 and P2 phases outperformed their monophasic counterparts in almost all electrochemical performance parameters.Operando synchrotron XRD measurements obtained for the monophasic P3 and biphasic P2/P3 samples revealed the absence of the O3 phase during cycling.The high structure stability and faster Na^(+)transport kinetics in the biphasic samples underpins the enhancement of electrochemical properties in the Al-substituted P3/P2 cathodes.These results highlight fixed oxidation state lines as a novel tool to identify and design layered oxide cathodes for Na-ion batteries in pseudo-ternary diagrams involving Jahn-Teller active cations.

关 键 词：Layered oxides Biphasic cathode Operando Synchrotron XRD Electrochemical behavior Cyclic performance 

分 类 号：TM912[电气工程—电力电子与电力传动] O646[理学—物理化学]