Статья

Significant Role of Al in Ternary Layered Double Hydroxides for Enhancing Electrochemical Performance of Flexible Asymmetric Supercapacitor

Xiaorui GaoDepartment of Materials Science and Engineering National University of Singapore 117574 Singapore SingaporeXimeng LiuDepartment of Materials Science and Engineering National University of Singapore 117574 Singapore SingaporeDajun WuJiangsu Laboratory of Advanced Functional Materials Department of Physics and Electronic Engineering Changshu Institute of Technology Changshu 215500 P. R. ChinaBin QianJiangsu Laboratory of Advanced Functional Materials Department of Physics and Electronic Engineering Changshu Institute of Technology Changshu 215500 P. R. ChinaZongkui KouDepartment of Materials Science and Engineering National University of Singapore 117574 Singapore SingaporeZhenghui PanDepartment of Materials Science and Engineering National University of Singapore 117574 Singapore SingaporeYajun PangDepartment of Materials Science and Engineering National University of Singapore 117574 Singapore SingaporeLinqing MiaoDepartment of Materials Science and Engineering National University of Singapore 117574 Singapore SingaporeJohn WangDepartment of Materials Science and Engineering National University of Singapore 117574 Singapore Singapore

2019en

ABI

Аннотация

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.

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Идентификаторы

DOI: 10.1002/adfm.201903879

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