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Significant Role of Al in Ternary Layered Double Hydroxides for Enhancing Electrochemical Performance of Flexible Asymmetric Supercapacitor
Author(s) -
Gao Xiaorui,
Liu Ximeng,
Wu Dajun,
Qian Bin,
Kou Zongkui,
Pan Zhenghui,
Pang Yajun,
Miao Linqing,
Wang John
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201903879
Subject(s) - materials science , layered double hydroxides , supercapacitor , electrochemistry , nanosheet , ternary operation , capacitance , chemical engineering , anode , nanowire , nanotechnology , electrode , hydroxide , chemistry , programming language , computer science , engineering
Abstract The Al effect on the electrochemical properties of layered double hydroxides (LDHs) is not properly probed, although it is demonstrated to notably promote the capacitive behavior of LDHs. Herein, ternary NiCo 2 Al x layered double hydroxides with varying levels of Al stoichiometry are purposely developed, grown directly on mechanically flexible and electrically conducting carbon cloth (CC@NiCo 2 Al x ‐LDH). Al plays a significant role in determining the structure, morphology, and electrochemical behavior of NiCo 2 Al x ‐LDHs. At an increasing level of Al in NiCo 2 Al x ‐LDHs, there is a steady evolution from 1D nanowire to 2D nanosheets. The CC@NiCo 2 Al‐LDH at an appropriate level of Al and with the nanowire–nanosheet mixed morphology exhibits both significantly enhanced electrochemical performance and excellent structural stability, with about a 2.3‐fold capacitance of NiCo 2 ‐OH. When applied as the anode in a flexible asymmetric supercapacitor (ASC), the CC@NiCo 2 Al‐LDH gives rise to a remarkable energy density of 44 Wh kg −1 at the power density of 462 W kg −1 , together with remarkable cyclic stability with 91.2% capacitance retention over 15 000 charge–discharge cycles. The present study demonstrates a new pathway to significantly improve the electrochemical performance and stability of transition metal LDHs, which are otherwise unstable in structure and poorly performing in both rate and cycling capability.