“…With the increased of the scan rate, the current response also increased without any obvious changes in the shape of the CV, meaning a good rate capability of the active materials 41 , 42 . Furthermore, the anodic peaks shifted positively and cathodic peaks shifted negatively, respectively, which was mainly due to the internal resistance of electrode 8 , 43 . Figure 5 Electrochemical capacitive properties of LDH-CNFs, LDH-CNTs, LDH-RGO and LDH-RGO-CNFs composites tested using a three-electrode system in 6 M KOH solution.…”
A novel NiFe-LDH/RGO/CNFs composite was produced by using a facile one-step hydrothermal method as electrode for supercapacitor. Compared with NiFe-LDH/CNFs, NiFe-LDH/CNTs and NiFe-LDH/RGO, NiFe-LDH/RGO/CNFs demonstrated a high specific capacitance of 1330.2 F g−1 at 1 A g−1 and a super rate capability of 64.2% from 1 to 20 A g−1, indicating great potential for supercapacitor application. Additionally, an asymmetric supercapacitor using NiFe-LDH/RGO/CNFs composite as positive electrode material and activated carbon as negative electrode material was assembled. The asymmetric supercapacitor can work in the voltage range of 0–1.57 V. It displayed high energy density of 33.7 W h kg−1 at power density of 785.8 W kg−1 and excellent cycling stability with 97.1% of the initial capacitance after 2500 cycles at 8 A g−1. Two flexible AC//LDH-RGO-CNFs ASC devices connected in series were able to light up a red LED indicator after being fully charged. The results demonstrate that the AC//LDH-RGO-CNFs ASC has a promising potential in commercial application.
“…With the increased of the scan rate, the current response also increased without any obvious changes in the shape of the CV, meaning a good rate capability of the active materials 41 , 42 . Furthermore, the anodic peaks shifted positively and cathodic peaks shifted negatively, respectively, which was mainly due to the internal resistance of electrode 8 , 43 . Figure 5 Electrochemical capacitive properties of LDH-CNFs, LDH-CNTs, LDH-RGO and LDH-RGO-CNFs composites tested using a three-electrode system in 6 M KOH solution.…”
A novel NiFe-LDH/RGO/CNFs composite was produced by using a facile one-step hydrothermal method as electrode for supercapacitor. Compared with NiFe-LDH/CNFs, NiFe-LDH/CNTs and NiFe-LDH/RGO, NiFe-LDH/RGO/CNFs demonstrated a high specific capacitance of 1330.2 F g−1 at 1 A g−1 and a super rate capability of 64.2% from 1 to 20 A g−1, indicating great potential for supercapacitor application. Additionally, an asymmetric supercapacitor using NiFe-LDH/RGO/CNFs composite as positive electrode material and activated carbon as negative electrode material was assembled. The asymmetric supercapacitor can work in the voltage range of 0–1.57 V. It displayed high energy density of 33.7 W h kg−1 at power density of 785.8 W kg−1 and excellent cycling stability with 97.1% of the initial capacitance after 2500 cycles at 8 A g−1. Two flexible AC//LDH-RGO-CNFs ASC devices connected in series were able to light up a red LED indicator after being fully charged. The results demonstrate that the AC//LDH-RGO-CNFs ASC has a promising potential in commercial application.
“…An anionic polyelectrolyte has been used for morphology control in a self‐assembling hydrothermal synthesis method. [ 195 ] A rosette‐type morphology ( Figure 12 ) has been developed, which allowed good electrolyte access and enhanced capacity. [ 195 ]…”
Section: Hydroxide Materialsmentioning
confidence: 99%
“…Considerable efforts have been made to improve electrochemical performance of complex hydroxides by the development of composites, containing other capacitive materials, such as oxides, graphene, and activated carbon. [ 190–194 ] The development of core–shell Ni‐Al layered double hydroxide/CNT composites [ 195 ] allowed the fabrication of electrodes with active mass of 50 mg cm −2 . CNT served as a conductive backbone for the layered Ni‐Al LDH nanosheets.…”
Pseudocapacitive materials are used for supercapacitor applications due to their exceptionally high capacitance and low cost. Good capacitive performance of the pseudocapacitive materials at high active mass loadings is vital for the development of the next generation of supercapacitor devices. This review describes recent advances in materials and nanotechnologies, which allows the development of advanced pseudocapacitive devices with high active mass. An important breakthrough is the discovery of novel dispersing and capping agents for the colloidal processing of nanoparticles. Particularly important are novel co‐dispersants that exhibit enhanced adsorption on materials of different types, such as inorganic nanoparticles, carbon nanotubes, and graphene. Conceptually new strategies are designed to fabricate coated particles. Recent innovations pave the way for the development of multifunctional redox‐active dopants‐dispersants and dopants‐oxidants to manufacture conductive polymer composites. Among the most important advances in nanotechnology is the development of template methods and heterocoagulation techniques for composite manufacturing. The progress in the design of novel surface modification techniques and materials, discovery of advanced anchoring groups, and development of liquid–liquid extraction allows agglomerate‐free processing of nanomaterials and composites. This review describes fundamental aspects of novel technologies and their applications in the manufacturing of pseudocapacitive devices for energy storage.
“…Liu and Huang reported a Ni/Al LDHs synthesized by hydrothermal method has a specific capacity of 268.6 and 294.8 mAh g −1 at 1 A g -1 , respectively [30,31]. In addition, the composites of Ni/Al LDHs with porous carbon, nickel foam or graphene have attracted lots of researcher's attentions [32][33][34][35][36]. Yang et al have reported Ni/Al LDHs/C composite possessing a specific capacity of 127.1-282.5 mAh g −1 at 1 A g -1 with a cycling life of 1,000 cycles [32][33][34][35].…”
Nickel-based hydroxides with excellent electrochemical performance have been considered as cathode materials for Ni/MH batteries. In this paper, a Ni/Al layered double hydroxides (Ni/Al LDHs) material with three-dimensional (3D) spherical structure is synthesized by a facile stable dual complexation-precipitation method. SEM images show that the obtained Ni/Al LDHs possess 3D spherical structure composed of nanosheets. XRD and CV tests indicate that doping of Al increases the distance between Ni-Al layers, greatly improving the specific capacity of the obtained materials. The electrochemical tests show that the specific capacity of the obtained material with 18% Al is up to 383.4 mAh g −1 at a current density of 1 A g −1. In addition, when the current density is further increased to 10 and 20 A g −1 , the specific capacity of this material still maintains 345.0 mAh g −1 and 307.9 mAh g −1 , respectively, which implies that this cathode material can provide remarkable power densities. Moreover, the material composed of Ni/Al LDHs keeps 97.6% initial capacity after 5,000 cycles at a current density of 10 A g −1 , showing an excellent cycling stability and durability.
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