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Significantly Enhanced Electrochemical Redox for High‐Performance Electrochemical Capacitor via Active Ion‐Tunnel Oriented BaCoF 4 Electrodes
Author(s) -
Guo Changjin,
Xie Jiyang,
Wang Jing,
Li Lun,
Zhu Zhu,
Xie Lin,
Mao Yongyun,
Hu Wanbiao
Publication year - 2021
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.202003734
Subject(s) - electrochemistry , materials science , electrolyte , redox , chemical engineering , electrode , capacitance , supercapacitor , nanotechnology , inorganic chemistry , chemistry , engineering , metallurgy
Active plane and specific morphology with reduced particle sizes have long been considered a promising strategy to achieve superior electrochemical properties, but the active sites involved may not be sufficiently utilized or the surface atomic configurations may obscure the activity. Herein, a novel structural “active orientation” strategy is developed to overcome the aforementioned shortcomings and improve the efficiency at active sites. A transition‐metal fluoride BaCoF 4 is well controlled to thin the dimensions along an active [ 3 1 ¯ 0 ] orientation through a sodium dodecyl benzene sulfonate assisted solution chemistry route. The active orientation facilitates the opening of the ionic pathways, for example, OH – in the electrolyte, to take full advantage of the redox activity of the electrochemically active Co 2+ /Co 3+ cations in [ 3 1 ¯ 0 ] ‐BaCoF 4 , resulting in significantly enhanced electrochemical redox performance. A high specific capacitance (692 F g −1 at 1 A g −1 in 6 m KOH electrolyte) is achieved owing to active‐tunnels orientation, ≈five‐fold higher compared to its bulk counterpart. Strikingly, the asymmetric electrochemical capacitor (AEC) fabricated with [ 3 1 ¯ 0 ] ‐BaCoF 4 and activated carbon exhibits an ultrahigh energy density of 147.7 Wh kg −1 at a power density of 1.025 kW kg −1 (also >100 Wh kg −1 at 5 kW kg −1 ), much higher than the majority of existing AEC systems.