Elucidation of the Jahn-Teller effect in a pair of sodium isomer

Peng Fei Wang, Ting Jin, Jiaxun Zhang, Qin Chao Wang, Xiao Ji, Chunyu Cui, Nan Piao, Sufu Liu, Jijian Xu, Xiao Qing Yang, Chunsheng Wang

Research output: Contribution to journalArticlepeer-review

73 Scopus citations

Abstract

Jahn-Teller distorted Mn(III) (t2g3eg1) ions play a key role in the performance of manganese-based layered oxides. Here we show that there is an obvious relationship between the Jahn-Teller distortion of a trivalent manganese and the electrochemistry in a pair of Na isomer, namely orthorhombic and hexagonal P2-type Na2/3Mn0.9Ti0.1O2 having the same composition. It is found that more reversible phase transformations, higher working voltage and faster Na diffusion correlated with Jahn-Teller effect are found for distorted P′2-Na2/3Mn0.9Ti0.1O2 upon Na+ ions extraction/insertion. Such Jahn-Teller distorted Mn assisted Na migration enables that the orthorhombic Na2/3Mn0.9Ti0.1O2 delivers a high specific capacity of 204.0 mA h g−1 with a 2.7 V average working voltage, reaching 550 Wh Kg−1 with both better cycle stability (a capacity retention of 82.3% after 100 cycles) and enhanced rate capability (97.8 mA h g−1 cycled at 10C) in Na cell in contrast with undistorted Na2/3Mn0.9Ti0.1O2. This strategy for understanding the Jahn-Teller effect of P2-type compounds at orbital energy level grasps new insight into designing high energy density positive electrode materials for Na-ion batteries.

Original languageEnglish
Article number105167
JournalNano Energy
Volume77
DOIs
StatePublished - Nov 2020
Externally publishedYes

Keywords

  • Cathode
  • Electrochemistry
  • Jahn-Teller effect
  • Sodium isomer
  • Sodium-ion batteries

Fingerprint

Dive into the research topics of 'Elucidation of the Jahn-Teller effect in a pair of sodium isomer'. Together they form a unique fingerprint.

Cite this