Miniaturization of transition metal hydroxides to hydroxide dots: A direction to realize giant cyclic stability and electrochemical performance

Abstract

Binary metal hydroxides have tailored to quantum size in situ by manipulating the solvent medium in the co-precipitation process. Bimetallic cobalt-nickel hydroxide dots reveal hydrotalcite structure, and the mean hydrodynamic diameter is restricted to 2.5 nm when Co:Ni molar ratio 1:1. The bandgap values obtain around 2.64 eV using Tauc relation, which is within the quantum confinement region. The fitting results of X-ray photoelectron spectroscopy suggested the presence of redox couple Co 2+ , Co 3+ , Ni 2+ , and Ni 3+ in the hydroxides dots, which facilitates more electroactive sites. Again, excellent stability of hydroxide dots in solvent medium obtained by measuring T2 relaxation time. The binary dots electrode exhibits excellent pseudocapacitance performance with specific capacitance of 1926 F g À1 (221 mAh g À1 ) at 1 A g À1 with outstanding cycling retention of ~96% up to 20 000 cycles. Parallelly, an asymmetric supercapacitor device has been assembled by monitoring different mass loading of active material as +Ve and carbon black as ÀVe electrode cells. The ASC device utilizes to brighten a commercial LED to validate the electrode. Also, the specific capacitance of the ASC device has been calculated about 250 F g À1 (353 mAh g À1 ) with a holding energy density of 85 W h kg À1 .

Two-dimensional layered nickel-based coordination polymer for supercapacitive performance

“…to store the charge on the electrode/electrolyte interface by non-faradic (charge-separation) reaction. 4,5 Besides, a pseudocapacitor utilizes transition metal hydroxides/oxides (TM-OH/TM-O) and conducting polymer to store the charge on the electroactive surface by faradaic reversible redox reaction. 6 Substantial research has been carried out to develop alternative transition metals oxides/conducting polymer composites to achieve higher specific capacitance and energy density.…”

Gelatin-assisted co-exfoliation of graphene nanoplatelets/MoS2for high-performance supercapacitors

“…6 From the diverse materials determined as electrode materials for supercapacitors, especially metal oxides/hydroxides, conducting polymers, 2D based layered materials, etc. [7][8][9][10] Two-dimensional materials (2D) such as MoS 2 , WS 2 , graphene and graphene nanoplatelets (GNP) [11][12][13] are found to be fascinating electrode materials due to their better mechanical strength, thermal and electrical conductivity. 14 Due to their efficient electrical conductivity, carbonaceous compounds are typically used as electrically conductive additives in electrochemical energy storage devices.…”

Design of a High-Efficiency Bifunctional Electrocatalyst: Rich-Nitrogen-Doped Reduced Graphene Oxide-Modified Carbon Cloth-Growing Nickel–Iron Complex Oxides for Overall Water Splitting

“…The increasing consumption of fossil energy has received extensive attention from researchers all over the world. 1,2 How to cherish the existing nonrenewable resources while developing and utilizing clean energy is of widespread concern. 3,4 The excessive consumption and exploitation of fossil energy has led to a large number of greenhouse gas emissions, which has mainly caused the global warming.…”

“…7,8 From the perspective of energy transformation pattern, it is a general trend to replace the traditional fossil energy with clean energy sources such as hydrogen. 2,9 Hydrogen is one kind of zero-carbon emission energy. The product of hydrogen after combustion is H 2 O, and H 2 O molecules can produce H 2 and O 2 by electrochemical decomposition.…”

“…At present, the problem of global warming is a serious challenge faced by the international community. The increasing consumption of fossil energy has received extensive attention from researchers all over the world. , How to cherish the existing nonrenewable resources while developing and utilizing clean energy is of widespread concern. , The excessive consumption and exploitation of fossil energy has led to a large number of greenhouse gas emissions, which has mainly caused the global warming. , Thus, greenhouse gas emissions were limited and reduced with the target of mitigating the global temperature rise. , From the perspective of energy transformation pattern, it is a general trend to replace the traditional fossil energy with clean energy sources such as hydrogen. , Hydrogen is one kind of zero-carbon emission energy. The product of hydrogen after combustion is H 2 O, and H 2 O molecules can produce H 2 and O 2 by electrochemical decomposition. , Definitely, hydrogen acts as a renewable energy source that meets our demand.…”