Insights into Ti doping for stabilizing the Na2/3Fe1/3Mn2/3O2 cathode in sodium ion battery

Iron- and manganese-based layered metal oxides, as cathodes for sodium ion batteries, have received widespread attention because of the low cost and high specific capacity. However, the Jahn-teller effect of Mn3+ ions and the resulted unstable structure usually lead to continuously capacity decay. Herein, Titanium (Ti) has been successfully doped into Na2/3Fe1/3Mn2/3O2 to suppress the Jahn-Teller distortion and improve both cycling and rate performance of sodium ion batteries. In situ high-energy synchrotron X-ray diffraction study shows that Ti-doped compound (Na2/3Fe1/3Mn0.57Ti0.1O2) can maintain the single P2 phase without any phase transition during the whole charging/discharging process. Various electrochemical characterizations are also applied to explore the better kinetics of sodium ions transfer in the Na2/3Fe1/3Mn0.57Ti0.1O2. This work provides a comprehensive insight into the Ti-doping effects on the performance from both structural and electrokinetic perspectives. (C) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Iron- and manganese-based layered metal oxides have attracted attention as cathodes for sodium-ion batteries due to their low cost and high specific capacity. This study successfully doped titanium (Ti) into Na2/3Fe1/3Mn2/3O2 to suppress the Jahn-Teller effect and improve the cycling and rate performance of sodium-ion batteries.