Bimetallic Co–W–S Chalcogenides Confined in N,S-Codoped Porous Carbon Matrix Derived from Metal–Organic Frameworks for Highly Stable Electrochemical Supercapacitors

Abstract

Transition-metal dichalcogenides are gaining much interest in the energy storage sector due to the two-dimensional (2D) nature and conductivity of the materials. However, single transition-metal dichalcogenides are not stable, preventing their practical use in real devices. Herein, we demonstrate the synthesis of binary metal dichalcogenides (Co−W−S) via carbonization of zeolitic imidazolate framework (ZIF-67), a subclass of metal−organic frameworks, encapsulated with phosphotungstic acid (PTA@ZIF-67). The morphology and surface functional groups of the as-synthesized Co−W−S composite are characterized via field-emission scanning electron microscopy (FESEM), highresolution transmission electron microscopy (HRTEM), and Fourier transform infrared (FTIR) spectroscopy. Furthermore, the crystal structure and elemental composition of the fabricated Co−W−S composite are elucidated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Upon testing its electrochemical performance as a supercapacitor electrode, the fabricated Co−W−S@N,S-codoped porous carbon (N,S-PC) shows exceptional specific capacitance (1929 F g −1 at 5 mV s −1 ). Furthermore, the constructed asymmetric supercapacitor device using Co−W−S@N,S-PC and activated carbon as positive and negative poles, respectively, displays superior energy density and power density of 32.9 Wh kg −1 and 700.2 W kg −1 , respectively, with high Columbic efficiency over 10 000 charge/discharge cycles at 10 A g −1 .

CuCo LDHs Coated CuCoTe Honeycomb‐Like Nanosheets as a Novel Anode Material for Hybrid Supercapacitors

“…As shown in Figure 7g and Table S1, Supporting Information, the values of energy and power densities of the proposed HSC device are larger than the values of recently reported MOF derived transition metal chalcogenide‐based SCs. [ 21,49–54 ] To use the HSC in any practical application, cycling stability is very important. Hence, the cycling stability test was carried out for up to 5000 continuous GCD cycles.…”

A mesoporous ternary transition metal oxide nanoparticle composite for high-performance asymmetric supercapacitor devices with high specific energy

“…Also, at low frequency, the Warburg line is related to the diffusion resistance. 39 A long-term stability test was carried out at 10 A g À1 to investigate the durability of the assembled TMN NPs//MPDC device over 11 000 charge/discharge cycles. Fig.…”

“…6d. Please do not adjust margins Please do not adjust margins related to the diffusion resistance 39 . Fig.…”

Recent Developments of Transition Metal Compounds-Carbon Hybrid Electrodes for High Energy/Power Supercapacitors

“…Moreover, 91% of its initial capacity could be retained after 10,000 cycles at 20 A g −1 , showing super-fast energy storage capacity and long cycle life. In another article, Mohamed et al [ 131 ] fabricated Co-W-S composites in an N, S co-doped porous carbon matrix (Co-W-S@N, S-PC) using PTA@ZIF-67 as a precursor via a simple carbonization method. Compared with the Co 1− x S@N, S-PC, the introduction of W atom could not only increase the redox activity of transition metal redox centers, but also provide additional faradaic pseudocapacitance.…”

“…Defects, such as vacancies, edges, grain boundaries, substitutional impurities, and so on, always play significant roles in improving geometric and electronic structures of TMCs [ 134 ]. Different defects often play different functions in improving the electrochemical performance of TMCs, such as vacancies increasing more active sites and enhancing conductivity [ 135 , 136 ], substitutional impurities providing additional capacitances and so on [ 131 , 137 ]. Specifically, the vacancies including metal vacancies and nonmetallic vacancies have been extensively explored to accelerate the intrinsic conductivity and redox activity of TMCs for supercapacitors [ 136 , 138 , 139 ].…”