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Construction of Hierarchical K 1.39 Mn 3 O 6 Spheres via AlF 3 Coating for High‐Performance Potassium‐Ion Batteries
Author(s) -
Zhao Shuoqing,
Yan Kang,
Munroe Paul,
Sun Bing,
Wang Guoxiu
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201803757
Subject(s) - materials science , potassium , electrochemistry , cathode , coating , chemical engineering , ion , diffusion , potassium ion battery , nanotechnology , electrode , chemistry , metallurgy , thermodynamics , physics , organic chemistry , engineering , lithium vanadium phosphate battery
Potassium‐ion batteries are attracting great interest for emerging large‐scale energy storage owing to their advantages such as low cost and high operational voltage. However, they are still suffering from poor cycling stability and sluggish thermodynamic kinetics, which inhibits their practical applications. Herein, the synthesis of hierarchical K 1.39 Mn 3 O 6 microspheres as cathode materials for potassium‐ion batteries is reported. Additionally, an effective AlF 3 surface coating strategy is applied to further improve the electrochemical performance of K 1.39 Mn 3 O 6 microspheres. The as‐synthesized AlF 3 coated K 1.39 Mn 3 O 6 microspheres show a high reversible capacity (about 110 mA h g −1 at 10 mA g −1 ), excellent rate capability, and cycling stability. Galvanostatic intermittent titration technique results demonstrate that the increased diffusion kinetics of potassium‐ion insertion and extraction during discharge and charge processes benefit from both the hierarchical sphere structure and surface modification. Furthermore, ex situ X‐ray diffraction measurements reveal that the irreversible structure evolution can be significantly mitigated via surface modification. This work sheds light on rational design of high‐performance cathode materials for potassium‐ion batteries.