Evaluation of electrochemical performance and redox activity of Fe in Ti doped layered P2-Na0.67Mn0.5Fe0.5O2 cathode for sodium ion batteries. (1st June 2021)

• Record Type: Journal Article
• Authors: Darbar, Devendrasinh; Muralidharan, Nitin; Hermann, Raphaël P.; Nanda, Jagjit; Bhattacharya, Indranil
• Is Part Of: Electrochimica acta. Volume 380(2021)
• Publication Date: 2021-06-01
• Subjects: Jahn Teller distortion -- P2-type layered cathode -- Sodiation/de-sodiation -- Sodium batteries -- Ti doping; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2021.138156
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Here, we report a wet synthesis-based titanium doping strategy to improve the structural stability and electrochemical performances, such as cycling stability and rate capability, of P2-type Na0.67 Fe0.5 Mn0.5 O2 layered oxide cathodes. Through Ti 4+ doping aimed at replacing some of the Mn and Fe atoms in the crystal structure, effective mitigation of the Jahn Teller distortion caused by active Mn 3+ before charging and Fe 4+ after charging was achieved. X-ray diffraction (XRD), Raman spectroscopy, Electrochemical Impedance Spectroscopy (EIS) and Mössbauer spectroscopy were used to investigate the effects of the Ti 4+ dopant before and after cycling. It was observed that Ti 4+ doping increased the Na layer thickness, minimized the lattice volume strain, showed better structural stability, minimally decreased Fe migration to the Na layer, and lowered charge transfer resistance in these P2-type cathodes. Overall, our reported synthesis methodology and electrochemical characterizations highlight the feasibility of Ti doping in sodium layered oxide P2-type cathodes. Graphical abstract: Ti doped NFM increase the Na layer thickness in the crystal structure, improve the rate performances, minimized the lattice volume strain, showed better structural stability and lowered charge transfer resistance in these P2-type cathodes. Image, graphical abstract