Enhancing electrochemical performance of electrode material via combining defect and heterojunction engineering for supercapacitors

Construction of Cu-Doped Ni–Co-Based Electrodes for High-Performance Supercapacitor Applications

“…Before testing, the electrodes to be measured were first immersed in the electrolyte of 2 M KOH for 5 h and were continuously soaked at scan rates of 5 mV/s and 20 mV/s in a CV system, which were aimed to wet the materials well and obtain a relatively stable capacitance. The formulas related to the electrochemical parameters are as follows: , where I represents the charge and discharge current (A), Δt is discharge time (s), I/m is the discharge current density (A/g), m and S are the mass loading (g) and area (cm 2 ) of the working electrode (1 cm × 1 cm), and ΔV is the voltage window (V) during the charge and discharge process. Furthermore, the performance parameters about ASC devices are fully measured at a two-electrode electrochemical workstation.…”

Three-dimensional Ni0.85Se@ZnSe nanostructures on carbon cloth for flexible asymmetric battery-type supercapacitors

“…42 Meanwhile, the heterostructure can induce charge redistribution at the contact interface, which can effectively accelerate the diffusion and transfer of electrolyte ions and electrons, improve the electrochemical kinetics, and optimize the electrochemical performance. 28 In addition, the Ni 0.85 Se@ZnSe-10 CC electrode has the longest discharge time and highest specific capacity with the maximum capacity of 1927 F g −1 at 1 A g −1 , which is also consistent with the above CV results, while the significant GCD variations of the three Ni 0.85 Se@ZnSe CC electrodes might be ascribed to the specific surface areas and active sites of the different electrodes prepared at the scan rates of 5, 10 and 20 mV s −1 . At the lower or larger scan rates (5 or 20 mV s −1 ), the decreased specific surface area or active sites are much disadvantageous to electrochemical performance improvement.…”

“…27 More importantly, the synergistic effect of bimetallic selenides through chemical bonds of different metal ions and the construction of heterostructured compounds will accelerate the diffusion and transfer of electrolyte ions and electrons, improve electrochemical kinetics, and further improve the performance of the electrochemical performance of supercapacitors. 28 For instance, Tian's group 29 reported the synthesis of NiSe nanorod arrays on nickel foam by a one-pot hydrothermal method, which exhibited ultrahigh areal capacitance, and the corresponding NiSe NRA/NF//RGO ACS delivered an energy density of 38.8 W h kg −1 at a power density of 629 W kg −1 . Sui et al 30 synthesized a layered NiCo 2 O 4 @Ni 0.85 Se core–shell structure directly on nickel foam, showing a high capacitance of 1454 F g −1 , and the NiCo 2 O 4 @Ni 0.85 Se//AC ASC device showed the highest energy density and power density (29.3 W h kg −1 at 799 W kg −1 ).…”

Harnessing the Defects at Hetero‐Interface of Transition Metal Compounds for Advanced Charge Storage: A Review

“…The presence of defects can result in several unique properties, such as: 1) providing more active sites and enhanced cation adsorption, which can significantly improve the charge storage capacity of the electrode; 2) regulating the charge distribution at the interface and significantly promoting charge transfer and the intrinsic electronic conductivity, thereby accelerating the reaction kinetics. [ 131,145–148 ]…”

“…The presence of defects can result in several unique properties, such as: 1) providing more active sites and enhanced cation adsorption, which can significantly improve the charge storage capacity of the electrode; 2) regulating the charge distribution at the interface and significantly promoting charge transfer and the intrinsic electronic conductivity, thereby accelerating the reaction kinetics. [131,[145][146][147][148] Many studies on the vacancies in chemically bonded heterostructures have focused on the content of oxygen vacancies to provide more active sites, decrease the band gap, and significantly reduce the ion diffusion barrier. [149,150] The chemical reduction method is a simple way to introduce oxygen vacancies into the bulk material.…”