ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis of nickel, calcium and magnesium naphthalene diimide complexes as supercapacitor materials

Wajid Hussain, Maroof Ahmad Khan, Zhongkui Li, Muhammad Javed Iqbal, Ayyaz Mahmood, Tuncer Hökelek, Muhammad Naveed, Ali Raza Ayub, and Hui Li

Key Laboratory of Cluster Sciences of Ministry of Education Beijing Key Laboratory of Photoelectronic/ Electro Photonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, People’s Republic of China

E-mail: lihui@bit.edu.cn

Received: 7 March 2022  Accepted: 15 August 2022

Abstract:

Three novel coordination complexes [Ni(H₂L1)(DMF)] (Complex 1), [Ca(H₂L2)(DMF)] (Complex 2), and [Mg(H₂L2)] (Complex 3) have been synthesized hydrothermally using naphthalene diimide (NDI) ligands. Additionally, these complexes have been studied by single-crystal XRD, IR spectroscopy, TGA analysis, UV–visible spectroscopy, and Hirschfeld surface analysis. Complexes 1 and 2 are 2D polymers of coordination, whereas complex 3 is a 3D coordination framework. The electrochemical properties of the three complexes are determined using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) analysis, and their suitability as supercapacitor electrode materials is determined by fabricating working electrodes in 0.5 M TBAPF₆ electrolytes in a three-electrode cell. The capacitances of the three complexes are gravimetric 214 Fg⁻¹, 141 Fg⁻¹, and 127 Fg⁻¹ at 1 Ag⁻¹, respectively, with a voltage window of − 2.5 to 1.0 V and outstanding stability up to 6000 cycles with retentions of around 80%, 78%, and 77%, respectively. We assembled a symmetric device of complex 1 only (because complex 1 has a higher specific capacitance than the other two complexes) that exhibited remarkable electrochemical performance, with a high specific capacitance of 102 Fg⁻¹ at 0.5 Ag⁻¹ and an excellent energy density of 28 Whkg⁻¹. Additionally, the symmetric device demonstrated excellent cyclic stability over 5000 charge–discharge cycles at 8 Ag⁻¹ with capacitive retention of 98%. Moreover, DFT study has been carried out to support the results. The results indicate that the three coordination complexes with superior electrochemical characteristics have the potential to operate as capacitors.

Keywords: Nickel; Calcium; Magnesium; Naphthalene diimide; Coordination complex; Electrochemistry

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02442-3

Chemical Papers 76 (12) 7729–7743 (2022)