Construction of MOF-derived hollow Ni–Zn–Co–S nanosword arrays as binder-free electrodes for asymmetric supercapacitors with high energy density

Abstract

Mixed transition metal sulfides with hollow structures hold great promise for energy-related applications. However, most of them are in the powder form, which should be mixed with unwanted polymer binders and conductive agents. In this study, a facile two-step strategy has been developed to grow mesoporous and hollow Ni-Zn-Co-S nanosword arrays (NSAs) on a nickel foam (NF) substrate with robust adhesion, which involves the hydrothermal growth of bimetallic Zn-Co-ZIF NSAs on NF and subsequent transformation into hollow Ni-Zn-Co-S NSAs through the sulfurization process. Benefiting from the unique structural and compositional advantages as well as directly grown conductive substrate, the Ni-Zn-Co-S-0.33 NSAs/NF electrode exhibits the best electrochemical performance when investigated as a binder-free electrode for supercapacitors. Impressively, the Ni-Zn-Co-S-0.33 NSAs/NF electrode delivers a high areal capacity of 1.11 mA h cm at the current density of 10 mA cm, and the corresponding specific capacity is as high as 358.1 mA h g. Moreover, an asymmetric supercapacitor (ASC) device based on the Ni-Zn-Co-S-0.33 NSAs/NF as the positive electrode and BiO/NF as the negative electrode has been successfully fabricated, and can deliver a high energy density of 91.7 W h kg at a power density of 458 W kg and maintain the energy density of 66.9 W h kg at a high power density of 6696 W kg. The electrochemical results suggest that the hollow Ni-Zn-Co-S NSAs would possess great potential for applications in high-performance supercapacitors.

Room-Temperature Fabrication of a Nickel-Functionalized Copper Metal–Organic Framework (Ni@Cu-MOF) as a New Pseudocapacitive Material for Asymmetric Supercapacitors

“…MOFs are used as promising electrode materials in SCs [17,18,19]. According to the energy storage required for the application, there are two types of SCs formed from MOFs: (1) MOFs used as controlled templates or precursors for synthesizing mesoporous carbon, metal oxides, and metal sulfide via thermolysis or sulfurization [20,21,22,23,24,25,26], and (2) MOFs used as electroactive materials for SCs owing to their porous properties. To improve the electrochemical performance of MOFs, the supercapacitive properties of MOFs should be further evaluated [27,28,29,30].…”

Hollow S‐ZIF‐(1:2.5)@NixSy as Highly Efficient Catalyst for 4‐Nitrophenol and Dye Reduction

“…In the meantime, it can be seen from the Ni 2p spectrum presented in Figure d that the peak at 853.4 eV in Ni 2p 3/2 and the peak at 870.4 eV in Ni 2p 1/2 can be typically attributable to the Ni 2+ state, while the peaks at 855.6eV and 873.2eV conform to the Ni 3+ state. The peaks at 861.5 eV and 879.4 eV belong to satellite …”

Overview of transition metal-based composite materials for supercapacitor electrodes

“…Transition metal oxides hold promise for achieving high levels of energy storage, especially for SC electrode materials, featuring low cost, environmentally benign nature, and high theoretical capacitance. 19,[35][36][37][38][39][40][41] The strategies in building the structure of transition metal oxides such as designing particular nanoarchitectures, combining oxide composites with multiple oxidation states, and multiple transition metal oxides, demonstrate transition metal oxides as an advanced electrode material for high-energy and high-power density electrochemical storage devices.…”

“…This journal is © The Royal Society of Chemistry 2020 suldes show superior electrochemical characteristics over their oxide counterparts and exhibit enhanced electrical conductivity by two orders of magnitude and a greatly improved redox reaction. 3,11,12,41,[84][85][86][87] 3.1. Binary transition metal suldes (M x N y S z )…”