Synchronous Defect and Interface Engineering of NiMoO4 Nanowire Arrays for High-Performance Supercapacitors

Abstract

Developing high-performance electrode materials is in high demand for the development of supercapacitors. Herein, defect and interface engineering has been simultaneously realized in NiMoO4 nanowire arrays (NWAs) using a simple sucrose coating followed by an annealing process. The resultant hierarchical oxygen-deficient NiMoO4@C NWAs (denoted as “NiMoO4−x@C”) are grown directly on conductive ferronickel foam substrates. This composite affords direct electrical contact with the substrates and directional electron transport, as well as short ionic diffusion pathways. Furthermore, the coating of the amorphous carbon shell and the introduction of oxygen vacancies effectively enhance the electrical conductivity of NiMoO4. In addition, the coated carbon layer improves the structural stability of the NiMoO4 in the whole charging and discharging process, significantly enhancing the cycling stability of the electrode. Consequently, the NiMoO4−x@C electrode delivers a high areal capacitance of 2.24 F cm−2 (1720 F g−1) at a current density of 1 mA cm−2 and superior cycling stability of 84.5% retention after 6000 cycles at 20 mA cm−2. Furthermore, an asymmetric super-capacitor device (ASC) has been constructed with NiMoO4−x@C as the positive electrode and activated carbon (AC) as the negative electrode. The as-assembled ASC device shows excellent electrochemical performance with a high energy density of 51.6 W h kg−1 at a power density of 203.95 W kg−1. Moreover, the NiMoO4//AC ASC device manifests remarkable cyclability with 84.5% of capacitance retention over 6000 cycles. The results demonstrate that the NiMoO4−x@C composite is a promising material for electrochemical energy storage. This work can give new insights on the design and development of novel functional electrode materials via defect and interface engineering through simple yet effective chemical routes.

Dual-defect site regulation on MOF-derived P-Co3O4@NC@Ov-NiMnLDH carbon arrays for high-performance supercapacitors

“…Therefore, designing an electrode material with a large ion surface area, magnicent conductivity, stable electrochemical stability and a fast ion transport rate is the core of the eld of SCs. [9][10][11][12][13][14][15][16][17][18] Recently, layered double hydroxides (LDHs), have been broadly employed for high-performance SC materials owing to their unique dimensional structures brought by electrochemical performance advantages, such as admirable redox activity and notable anion exchange capacity. [19][20][21] However, the impoverished rate performance triggers a sluggish electron transfer rate, which will lead to limited future application.…”

“…Therefore, designing an electrode material with a large ion surface area, magnificent conductivity, stable electrochemical stability and a fast ion transport rate is the core of the field of SCs. 9–18…”

Energy Enhancement of a Nickel–Cobalt-Mixed Metallic Metal–Organic Framework Electrode and a Potassium Iodide Redox Mediator Bound with an Aqueous Electrolyte for High-Performance Redox-Aided Asymmetric Supercapacitors

“…Ren et al introduced a hierarchical doughnut-like Ni 3 S 2 @PPy core-shell heterostructure on the nickel foam electrode material, which reached a specific capacitance of up to 3148.0 mF cm –2 at a current density of 2.0 mA cm –2 . The study results of Wang et al presented excellent performance (1720 F g –1 ) and cycle stability performance . When cobalt ions were doped into Ni-MOFs to promote electrochemical conductivity, the mixed metal MOFs showed an increased surface area and pore volume when compared to those of Ni-MOFs.…”

Organic Crosslinked Polymer-Derived N/O-Doped Porous Carbons for High-Performance Supercapacitor

“…Theoretical research on and practical applications of supercapacitors have significantly progressed; however, insufficient energy density and high cost are still challenges requiring resolution [5][6][7]. Electrode materials, which can be divided into carbon materials [8,9], metal oxides [10,11], and conductive polymers [12,13], play an important role as core components in supercapacitors and are a key step in solving the existing problems. Among them, carbon materials are the most widely used electrode materials because of their high specific surface area, and good electrical conductivity and chemical stability [14][15][16].…”