Enhanced Electrochemical Performance of Biomass Porous Carbon Adsorption Congo Red

Biomass porous carbon has received widespread attention due to its application as electrode material for supercapacitors and adsorbent for difficult-to-degrade organic dyes. In this paper, biomass porous carbon KGL is prepared using ginkgo leaves as the precursor and KOH as the activator. Capitalizing on the adsorption property of porous carbon, an azo dye Congo red (CR) is confined into the nanopores of KGL to fabricate the KGL/CR electrode. The result suggests that KGL has good adsorption performance for organic dye and KGL/CR has excellent capacitance performance. When the CR concentration is 500 mg L-1, the adsorption capacity of KGL is 495 mg g-1. KGL/CR-500 displays elevated specific capacitance of 393 F g-1 at 1 A g-1 and excellent rate performance (76.3% capacitance retention at 10 A g-1). The capacitance retention after 10000 cycles maintains 99%. The symmetric supercapacitor has power density of 699.8 W kg-1 at an energy density of 16.4 Wh kg-1 and can power a light emitting diodes (LED). Our work provides the information that one is the treatment of organic dye wastewater, the other is development of electrochemical energy-storage materials, and may be expanded to the resource-utilization of other versatile effluent containing the redox groups.

MnCo2O4/g-C3N4 composite material preparation and its capacitance performance

MnCo2O4/g-C3N4 composite material was synthesized by the hydrothermal method, compared with MnCo2O4 without g-C3N4, it has excellent electrochemical performance. The composite material can reach a specific capacitance of 350 Fg[Formula: see text] at 1 Ag[Formula: see text]. The capacity retention rate is 96% after 1000 cycles at the rate of 2 Ag[Formula: see text]. Experiments show that g-C3N4 can effectively disperse and improve the conductivity of urchin-like MnCo2O4, and the composite of sufficient g-C3N4 can give full play to the performance of urchin-like MnCo2O4, provide faster electronic transport channels, effectively improve the ion migration rate, and make urchin-like MnCo2O4 increase the rate performance under high charge and discharge rates.

Nest-Like MnO2 Nanowire/Hierarchical Porous Carbon Composite for High-Performance Supercapacitor from Oily Sludge

In the aim to go beyond the performance tradeoffs of classic electric double-layer capacitance and pseudo-capacitance, composites made out of carbon and pseudo-capacitive materials have been a hot-spot strategy. In this paper, a nest-like MnO2 nanowire/hierarchical porous carbon (HPC) composite (MPC) was successfully fabricated by a controllable in situ chemical co-precipitation method from oily sludge waste. Due to the advantages of high surface area and fast charge transfer for HPC as well as the large pseudo-capacitance for MnO2 nanowires, the as-prepared MPC has good capacitance performance with a specific capacitance of 437.9 F g−1 at 0.5 A g−1, favorable rate capability of 79.2% retention at 20 A g−1, and long-term cycle stability of 78.5% retention after 5000 cycles at 5 A g−1. Meanwhile, an asymmetric supercapacitor (ASC) was assembled using MPC as the cathode while HPC was the anode, which exhibits a superior energy density of 58.67 W h kg−1 at the corresponding power density of 498.8 W kg−1. These extraordinary electrochemical properties highlight the prospect of our waste-derived composites electrode material to replace conventional electrode materials for a high-performance supercapacitor.

Synthesis and Characterization of Functionalized Hafnium Oxide Nanoparticles for Supercapacitor Applications

Functionalized metal oxide electrode material plays an important role in the energy application of the supercapacitor. In this work, the comparative study of super-capacitance performance of hafnium oxide (HfO2) and sulfonated hafnium oxide (S-HfO2) nanomaterials is reported. The HfO2 nanoparticles were synthesized by the precipitation method. Subsequently, the prepared HfO2 nanoparticles were functionalized using sulfuric acid (H2SO4). Further, the synthesized nanoparticles were characterized and confirmed by X-Ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, High-resolution transmission electron microscope (HR-TEM), Field-Emission scanning electron microscope (FE-SEM) and Energy Dispersive X-Ray spectroscopy (EDS) techniques. The electrochemical properties and ion transfer characteristics of the supercapacitor were investigated by the cyclic voltammeter (CV) and galvanostatic charge-discharge (GCD) experiments. Moreover, the internal resistances of the material (HfO2 and S-HfO2) were analysed using Electrochemical Impedance Spectroscopy

Combined Inductive and Capacitive NDE Technique for Insulator-Conductor Hybrid Structures

This paper presents a new inductance-capacitance non-destructive detection technique with a form of planar dual-mode sensor. The detection principle of the sensor in mode-L and mode-C was analyzed, and the feasibility of this new combination of inductance and capacitance nondestructive detection technique was demonstrated. A PCB sensor was designed and manufactured, a further research on the characteristic physical field of the designed sensor using finite element simulation software was presented. A suitable detection system was developed to realize this new dual-mode detection technique using this dual-mode detection sensor. Typical test pieces were prepared and tested. The detection results show that the proposed new inductance-capacitance technique can detect typical defects in both insulator and conductor layers of the insulator-conductor hybrid structure with a good balance of inductance and capacitance performance, indicating that this new detection technique can be further used for insulator-conductor hybrid structures non-destructive testing with the potential for structure detection, quantitative evaluation, damage imaging and other applications.