Hydrothermal Synthesis of NiCo₂O₄/Activated Carbon Composites for Supercapacitor with Enhanced Cycle Performance

Abstract

Owing to the advantages of the good conductive AC and high capacitive NiCo 2 O 4 , We prepared a series of NiCo 2 O 4 /AC composites by a hydrothermal method. The morphology of NiCo 2 O 4 /AC composites indicate the NiCo 2 O 4 nanoplates with diameters of about 0.5~1 mm and thickness of about 20 nm are coated on AC. The electrochemical investigation demonstrate that the specific capacitances of NCO-AC-3 (containing 47 % NiCo 2 O 4 ) are 273.5 F g À1 and the capacity retention still retains at 96 % (262.6 F g À1 ) after 3000 cycles at current density of 1 Ag À1 , especially, the cycling stability maintain more stable at high current density. Therefore, the low-cost NiCo 2 O 4 /AC composites can serve as a promising electrode material for high performance supercapacitors due to the synergistic effect between the electric double-layer capacitance of porous AC and the pseudocapacitance of NiCo 2 O 4 nanoplates.[a] Dr.

One‐Step Controllable Synthesis of Mesoporous MgCo2O4 Nanosheet Arrays with Ethanol on Nickel Foam as an Advanced Electrode Material for High‐Performance Supercapacitors

“…Meanwhile, spinel (AB 2 O 4 ) type TTMOs (e.g. NiCo 2 O 4 , NiFe 2 O 4 , and CoMn 2 O 4 ) have been widely investigated for electrochemical capacitor applications. TTMOs have extremely high theoretical capacitance (≈3000 F g −1 ) because the mass transportation, ion diffusion, and electron transfer have all been promoted.…”

“…[10][11][12][13] Currently,t ransition metal oxides( TMOs), especially ternary transition metal oxides( TTMOs), have becomeo ne of the hot topicsi nt he fieldo fe lectrode materials, owing to their multiple oxidation states, low cost, environmental friendliness,a nd high naturala bundance.M eanwhile, spinel (AB 2 O 4 )t ype TTMOs( e.g. NiCo 2 O 4 , [14][15][16] NiFe 2 O 4 , [17][18][19] and CoMn 2 O 4 ) [20][21][22] have been widely investigated for electrochemicalc apacitor applications.T TMOsh ave extremely high theoretical capacitance ( % 3000 Fg À1 )b ecause the mass transportation, ion diffusion, and electron transferh avea ll been promoted. Furthermore, the size and morphology of TTMOs electrode materials also have an effectontheir capacitance.…”

Highly Hydrophilic Carbon Dots' Decoration on NiCo2O4 Nanowires for Greatly Increased Electric Conductivity, Supercapacitance, and Energy Density

“…The specific capacitances ( C m ) of active material on the single electrode can be calculated by Equation , as described elsewherewhere I (A) and ∆ t (s) denote the discharge current and discharge time, while ∆ V (V) and m (g) refer to the potential window and the mass of the active material within the electrode, respectively. Notably, as shown in Figure c, CDs/NiCo 2 O 4 exhibits the higher specific capacitance of 2202 F g −1 at a current density of 1 A g −1 than NiCo 2 O 4 electrode . Moreover, CNCO‐3 presents the largest specific capacitance among all of the CDs/NiCo 2 O 4 samples (CNCO‐1–CNCO‐5), where they are 699, 1007, 2202, 944, and 810 F g −1 at a same current density, respectively, as shown in Figure S11 (Supporting Information).…”

NiCo2O4/C Core‐Shell Nanoneedles on Ni Foam for All‐Solid‐State Asymmetric Supercapacitors

“…Spinel nickel cobaltite (NiCo 2 O 4 ) is one of the most representative active materials for pseudocapacitors because of its high theoretical capacity, cost‐effective, natural abundance, and environmental friendliness . Nevertheless, the capacitance of NiCo 2 O 4 is far less than its theoretical value, which is generally caused by intrinsically poor electronic conductivity which restrict the transfer of electrons . The storage mechanism of pseudocapacitors is confined to the few nanometers of surface, while the thickness of electrode materials is generally dozens of nanometers or more, which limit the effective utilization of active materials .…”