New Energy Storage Option: Toward ZnCo₂O₄ Nanorods/Nickel Foam Architectures for High-Performance Supercapacitors

Abstract

Hierarchical ZnCo2O4/nickel foam architectures were first fabricated from a simple scalable solution approach, exhibiting outstanding electrochemical performance in supercapacitors with high specific capacitance (∼1400 F g(-1) at 1 A g(-1)), excellent rate capability (72.5% capacity retention at 20 A g(-1)), and good cycling stability (only 3% loss after 1000 cycles at 6 A g(-1)). All-solid-state supercapacitors were also fabricated by assembling two pieces of the ZnCo2O4-based electrodes, showing superior performance in terms of high specific capacitance and long cycling stability. Our work confirms that the as-prepared architectures can not only be applied in high energy density fields, but also be used in high power density applications, such as electric vehicles, flexible electronics, and energy storage devices.

A facile one-step approach to hierarchically assembled core–shell-like MnO2@MnO2 nanoarchitectures on carbon fibers: An efficient and flexible electrode material to enhance energy storage

“…54, 230.6, 215.3, 195.8, 161.1, and 132.5 F/g at current densities of 0.5, 0.75, 1, 1.5, 2.5, and 5 A/g, respectively, with a rate capability of 54%. Such excellent energy storage performance is higher than or comparable to most of the reported MnO 2 based pseudocapacitive materials, such as urchin-like MnO 2 hollow nanospheres (188 F/g at 0.5 A/g) [29], honeycomb MnO 2 @carbon fibers (58.28 F/g at 0.5 A/g) [32], and whisker-like MnO 2 on carbon fiber paper (106.4 F/g at 0.5 A/g) [57]. On increasing the current density, the specific capacitance values of the MnO 2 NSs@MnO 2 HNPAs on CC electrode decreased slowly, possibly due to the incomplete diffusion of electrolyte ions at high current densities.…”

“…have been extensively investigated as electrode materials for pseudocapacitors [23][24][25][26][27][28][29]. Among them, MnO 2 nanostructures (NSs) have received considerable attention because of their high theoretical specific capacitance, environmental friendliness, low cost, and low toxicity [30,31].…”

PVP assisted morphology-controlled synthesis of hierarchical mesoporous ZnCo 2 O 4 nanoparticles for high-performance pseudocapacitor

“…al[13] and Liu et. al[19] who used solvothermal and polyol refluxing method and synthesized ZnCo 2 O 4 with microsphere and nanorod morphology, respectively, got lower specific capacitance values compared to our synthesized ZnCo 2 O 4 NPs through a facile hydrothermal process with ring, oval and hexagonal morphology, respectively. Additionally, Niu et.…”

“…With effort to meet these challenges, various studies have been conducted for the past years. Different nanostructures have been developed such as nanorods [19], nanowires [20], nanocubes [21], microspheres [22], nanosheets [23] and core-shell hybrid nanostructures [24]. Despite of these developments, still there are more rooms for improvement such as improving the morphological structure through easier process and with use of low cost materials.…”

Template-free synthesis of hierarchical porous Co 3 O 4 microspheres and their application for electrochemical energy storage

“…In recent years, the research on high-capacity cathode of alkaline pseudocapacitive hybrid batteries focuses on metal oxides (NiO [5,6], and Co 3 O 4 [7][8][9], etc. ), binary metal oxides (NiCo 2 O 4 [10], and ZnCo 2 O 4 [11]), hydroxides (e.g., Co (OH) 2 [12,13], Ni(OH) 2 [14]) and metal sulfides (NiS and CoS [15,16]), which have significantly high-rate capacities and energy densities arising from faradic redox reactions and pairing with porous carbon anode, which stores energy using fast ion adsorption. These cathode materials generally possess high theoretical values (200-300 mAh g À1 ), but their practical utilization is still low because these active materials, albeit their other advantages, have drawbacks of poor rate capability and reversibility since they are kinetically unfavorable to support fast electron/ ion transport required by high power density.…”