Novel insights of structure evolution between ZIF and hydroxide via controlled doses of ammonium bifluoride and applications on battery supercapacitor hybrids

Journal article

Authors/Editors

CHUTIMA KONGVARHODOM

Strategic Research Themes

Innovative Materials, Manufacturing and Construction (Strategic Research Themes)

Publication Details

Author list: Cheng, Tsai-Mu; Wang, Su-Ching; Lee, Pin-Yan; Hsu, Chia-Shuo; Chen, Mei-Wei; Yougbaré, Sibidoug; Chen, Hsiao-Chien; Kongvarhodom, Chutima; Lin, Lu-Yin; Wu, Yung-Fu;

Publisher: Elsevier

Publication year: 2023

Volume number: 68

ISSN: 2352-152X

eISSN: 2352-152X

URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85159550243&doi=10.1016%2fj.est.2023.107709&partnerID=40&md5=381cc2a00097c5161ff444ee2f31b32c

Languages: English-Great Britain (EN-GB)

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Abstract

Metal organic framework is often post-treated to increase electrical conductivity and electroactivity for application on battery supercapacitor hybrids (BSH). An in-situ modification is previously proposed to replace post-treatments via incorporating ammonium fluoride (NH4F) during synthesizing zeolitic imidazolate framework-67 (ZIF67) to develop derivatives with excellent energy storage ability. Inspired by structure directing ability of ammonium group, high electronegativity of fluorine-based group, and time and money-saving process of in-situ modification, a novel structure directing agent (SDA), ammonium bifluoride (NH4HF2), is proposed in this study to design ZIF67 derivatives via the facile one-step solution process for the first time. The amounts of NH4HF2 and 2-methylimidazole are varied to fabricate a series of ZIF67 derivatives, and the SDA effects on physical and electrochemical properties are investigated. The highest specific capacitance (CF) of 1116.7 F/g and the capacity of 217.1 mAh/g are achieved for the optimal ZIF67 derivative at 20 mV/s, because of the thinnest layers with large surface area and abundant electrolyte contacts. The ZIF67 derivative and carbon electrodes are applied to fabricate a BSH, which displays a CF retention of 84.8% and Coulombic efficiency of 96.1% after measuring the charge/discharge curves at 1.0 A/g for 10,000 cycles, as well as the maximum energy density of 7.3 Wh/kg at the power density of 714.3 W/kg. © 2023

Keywords

2-methylimidazole, Ammonium bifluoride, Battery supercapacitor hybrid, In-situ modification, Structure directing agent, Zeolitic imidazolate framework-67