CoNi Layered Double Hydroxide Nanosheets Vertically Grown on Electrodeposited Dendritic Copper Substrates for Supercapacitor Applications

Abstract

Layered double hydroxides (LDHs) have attracted numerous interests in developing high-performance electrochemical supercapacitors (SCs). However, the anchored conductive substrates are critical in the high-dense growth of LDH with favorable crystal orientations for maximizing performances, in which the conventional amorphous carbon-based materials and microporous nickel foams cannot be fitted. Herein, we utilize the electrodeposited 3D dendritic copper as the conductive substrate for the vertical growth of CoNi-LDH nanosheets. The composite possesses excellent electrical conductivity, a high degree of crystallinity with (003) orientation, and a large surface area, resulting in an impressive specific capacitance of 5743 mF cm–2 at 1 mA cm–2 with 56.6% rate capability at 20 mA cm–2 and excellent cycling lifespan. In comparison, pure CoNi-LDH shows a smaller specific capacitance of 1798.18 mF cm–2 at 1 mA cm–2 with 46.1% rate capability at 20 mA cm–2. Such improved electrochemical performances of the composite electrode are possibly due to the sufficient exposure of the active centers, the shortened diffusion distance of electrolyte ions, and the synergistic interaction of the copper core and the LDH shell. The assembled asymmetric supercapacitor device based on the as-prepared composite anode and the activated carbon cathode exhibits an energy density of 0.33 mW h cm–2 at a large power density of 1.5 mW cm–2. This work reveals a facile and feasible strategy for improving the performances of LDH-based SC devices through the engineering of conductive substrates.

Mixed solvent-assisted synthesis of high mass loading amorphous NiCo-MOF as a promising electrode material for supercapacitors

“…The electrochemical performance of the synthesized sample was measured on a CHI 660E (Chenhua) electrochemical workstation, including cyclic voltammetry (CV), constant current charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS). The formulas for calculating the areal capacitance ( C a and C h ) are as follows: 34 where C a (F cm −2 ) and C h (mA h cm −2 ) are the areal capacitance, I (A) is the discharge current, t (s) is the discharge time, S (cm 2 ) is the geometrical area of the electrode and Δ V (V) is the potential window. 35…”

Doubly Doped Mg-Al-V2O74– Layered Double Hydroxide/Mo2CTx MXene Nanosheet Composites for Wear- and Corrosion-Resistant Coatings

“…LDH nanosheets are known as anionic clays, which are composed of positively charged metal layers, interlayer anions, and H 2 O molecules, which are currently one of the most thoroughly researched layered materials. , The general formula for LDHs is expressed as [M 2+ 1– x M 3+ x (OH) 2 x + (A n – ) x / n ] x + ·mH 2 O, where M 2+ (Mg 2+ , Ni 2+ , Zn 2+ , etc.) is the metal divalent, M 3+ (Al 3+ , Mn 3+ , Co 3+ , etc.)…”

Potential Oscillations During Cobalt–Nickel Electrodeposition in the Presence of Butynediol

“…In this work, our focus was to study the electrodeposition of CoNi, which is an important electrocatalytic material for energy reactions. − Butynediol has been used to control the roughness and texture of the CoNi alloy . Our previous study showed that the flux of butynediol and protons affects the electrochemical oscillation that involved adsorbed hydrogen and cobalt hydroxide during the electrodeposition of cobalt under quiescent conditions .…”