Open AccessElectrochemically Synthesis of Nickel Cobalt Sulfide for High‐Performance Flexible Asymmetric Supercapacitors
Author(s) -
Zhang Chunyan,
Cai Xiaoyi,
Qian Yao,
Jiang Haifeng,
Zhou Lijun,
Li Baosheng,
Lai Linfei,
Shen Zexiang,
Huang Wei
Publication year - 2018
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201700375
Subject(s) - nanosheet , supercapacitor , materials science , capacitance , cathode , anode , cobalt sulfide , nickel , electrochemistry , chemical engineering , nanotechnology , cobalt , graphene , energy storage , electrode , metallurgy , chemistry , power (physics) , physics , quantum mechanics , engineering
A lightweight, flexible, and highly efficient energy management strategy is highly desirable for flexible electronic devices to meet a rapidly growing demand. Herein, Ni–Co–S nanosheet array is successfully deposited on graphene foam (Ni–Co–S/GF) by a one‐step electrochemical method. The Ni–Co–S/GF composed of Ni–Co–S nanosheet array which is vertically aligned to GF and provides a large interfacial area for redox reactions with optimum interstitials facilitates the ions diffusion. The Ni–Co–S/GF electrodes have high specific capacitance values of 2918 and 2364 F g −1 at current densities of 1 and 20 A g −1 , respectively. Using such hierarchical Ni–Co–S/GF as the cathode, a flexible asymmetric supercapacitor (ASC) is further fabricated with polypyrrple(PPy)/GF as the anode. The flexible asymmetric supercapacitors have maximum operation potential window of 1.65 V, and energy densities of 79.3 and 37.7 Wh kg −1 when the power densities are 825.0 and 16100 W kg −1 , respectively. It's worth nothing that the ASC cells have robust flexibility with performance well maintained when the devices were bent to different angles from 180° to 15° at a duration of 5 min. The efficient electrochemical deposition method of Ni–Co–S with a preferred orientation of nanosheet arrays is applicable for the flexible energy storage devices.