Enhanced electrochemical supercapacitance of binder-free nanoporous ternary metal oxides/metal electrode

Single-step,in-situfabrication of flower-like NiCuMn hybrid oxyhydroxide electrodes for enhanced supercapacitor performance

The rational design of highly active and low-cost electrode material is very promising for energy storage applications. The development of supercapacitors with high energy/power density is an imperative and challenging research objective. Herein, we report a highly facile synthesis approach for developing unique nano-porous hybrid NiCuMn oxyhydroxide architecture with remarkable electrochemical energy storage characteristics. The process involves dealloying of Ni15Cu15Mn70alloy in an oxygen rich environment, resulting in a uniform 3-dimensional flower like morphology. The dealloyed electrode demonstrates ultra-high specific capacitance of 4110 F cm-3at a high current density of 20 mA cm-2. A symmetric device exhibits a high volumetric capacitance of 365 F cm-3at a current density of 10 mA cm-2with a large potential window of 1.7 V. Even at very high-power density of 850 W l-1, the device exhibits a high energy density of 146 Wh l-1along with remarkable cyclic stability of 95.4% after 10 000 cycles. The superior performance of nano-porous hybrid NiCuMn oxyhydroxide architecture was attributed to its unique microstructure that provides high surface area, and marginal internal resistance ensuring rapid charge transport.

Resent Development of Binder-Free Electrodes of Transition Metal Oxides and Nanohybrids for High Performance Supercapacitors - A Review

The entire world is aware of the serious issue of global warming and therefore utilizing renewable energy sources is the most encouraging steps toward solving energy crises, and as a result, energy storage solutions are necessary. The supercapacitors (SCs) have a high-power density and a long cycle life, they are promising as an electrochemical conversion and storage device. In order to achieve high electrochemical performance, electrode fabrication must be implemented properly. Electrochemically inactive and insulating binders are utilized in the conventional slurry coating method of making electrodes to provide adhesion between the electrode material and the substrate. This results in an undesirable "dead mass," which lowers the overall device performance. In this review, we focused on binder-free SCs electrodes based on transition metal oxides and composites. With the best examples providing the critical aspects, the benefits of binder-free electrodes over slurry-coated electrodes are addressed. Additionally, different metal-oxides used in the fabrication of binder-free electrodes are assessed, taking into account the various synthesis methods, giving an overall picture of the work done for binder-free electrodes. The future outlook is provided along with the benefits and drawbacks of binder-free electrodes based on transition metal oxides.

Metal-organic framework-derived porous ternary ZnCo2O4 nanoplate arrays grown on carbon cloth for simultaneous electrochemical determination of ascorbic acid, dopamine, and uric acid

Metal-organic frameworks derived from ternary metal oxide directly grown on the conductive substrate have attracted great interest in electrochemical sensing. In this work, metal-organic framework-derived ternary ZnCo₂O₄ nanoplate arrays that were grown on carbon cloth (ZnCo₂O₄ NA/CC) are fabricated and applied for the electrochemical determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Field emission scanning electron microscope (FESEM) reveals that a network-like CC substrate is covered with considerable nanoplate arrays, presenting a large specific area. X-ray photoelectron spectroscopy (XPS) demonstrates the nanoplate arrays to be composed of ZnCo₂O₄. Benefiting from the unique array morphology and ternary element composition, the ZnCo₂O₄ NA/CC shows desirable performances for simultaneous detection of AA, DA, and UA. The individual detection limits are 7.14 μM for AA, 0.25 μM for DA, and 0.33 μM for UA. Additionally, the ZnCo₂O₄ NA/CC is successfully applied for the quantitative determination of AA, DA, and UA in spiked serum samples, showing its great application potential.

Three-Dimensional Binder-Free Nanoarchitectures for Advanced Pseudocapacitors

The ever-increasing energy demands for electrification of transportation and powering of portable electronics are driving the pursuit of energy-storage technologies beyond the current horizon. Pseudocapacitors have emerged as one of the favored contenders to fill in this technology gap, owing to their potential to deliver both high power and energy densities. The high specific capacitance of pseudocapacitive materials is rooted in the various available oxidation states for fast surface or near-surface redox charge transfer. However, the practical implementation of pseudocapacitors is plagued by the insulating nature of most pseudocapacitive materials. The wealth of the research dedicated to addressing these critical issues has grown exponentially in the past decade. Here, we briefly survey the current progress in the development of pseudocapacitive electrodes with a focus on the discussion of the recent most exciting advances in the design of three-dimensional binder-free nanoarchitectures, including porous metal/graphene-based electrodes, as well as metal-atom/ion-doping-enhanced systems, for advanced supercapacitors with comparable energy density to batteries, and high power density.