Collaborative Improvement Electrochemical Properties of Supercapacitor Electrodes by Loading MoS2 Nanosheets on Biomass Hierarchical Porous Carbon

MoS2, a typical two-dimensional transition metal sulfide nanomaterial, has attracted much attention for supercapacitor electrode materials due to its high theoretical capacity. Herein, MoS2 nanosheets growing on a hierarchical porous carbon (HPGC) derived from pomelo peel are prepared via hydrothermal method. The curled MoS2 nanosheets uniformly grow and distribute on the conductive hierarchical porous carbon matrix, which made the electrodes materials possess a high specific surface area (320.2 m2/g). Simultaneously, the novel structure enhances the conductivity of MoS2, alleviates capacity attenuation and guarantees the interface stability. Furthermore, the MoS2/HPGC show a great enhancement in supercapacitor performance and deliver a remarkable specific capacitance of 411.4 F/g at the current density of 0.5 A/g. The initial capacitance retention rate is approximately 94.3% after 2000 cycles. It turns out that the synergistic effects between the MoS2 nanosheets and HPGC contribute to high specific capacity, excellent rate performance and ultra-long cycle life. This work provides a new idea for the design and development of MoS2 composites as the electrode materials of supercapacitors.

Electrochemical performance of composite electrodes based on rGO, Mn/Cu metal–organic frameworks, and PANI

Benzendicarboxylic acid (BDC)-based metal–organic frameworks (MOFs) have been widely utilized in various applications, including supercapacitor electrode materials. Manganese and copper have solid diamond frames formed with BDC linkers among transition metals chosen for MOF formation. They have shown the possibility to enlarge capacitance at different combinations of MOFs and polyaniline (PANI). Herein, reduced graphene oxide (rGO) was used as the matrix to fabricate electrochemical double-layer SCs. PANI and Mn/Cu-MOF's effect on the properties of electrode materials was investigated through electrochemical analysis. As a result, the highest specific capacitance of about 276 F/g at a current density of 0.5 A/g was obtained for rGO/Cu-MOF@PANI composite.

A Review on Synthesis and Characterization of Activated Carbon from Natural Fibers for Supercapacitor Application

Supercapacitors have gained much attention in recent years due to their promising characteristics, such as high specific capacitance, high power density, long cycle life, and environment-friendly nature. Usage of natural sources for activated carbon synthesis is a major focus by many researchers worldwide for discovering a replacement of existing supercapacitors. This review summarizes the methods used to synthesize activated carbon (AC) from various natural fiber, their physical and electrochemical characteristics, and the improvement of supercapacitor electrode performance. Previous research studies indicate the practicability of activated carbon derived from various natural fibers with superior electrochemical properties. The effect of activating reagents and temperature on the electrochemical performance for supercapacitor applications are also highlighted in this paper. Since the nature of activated carbon from fibers and its synthesizing methods would result in different properties, the Cyclic Voltammetry (CV) study is also thoroughly discussed on the specific capacitance together with charge/discharge test to observe the capacitance retention after several cycles. Finally, a detailed approach of converting biowaste materials to activated carbon for energy storage applications with environmental concerns is explored.

Direct Carbonization of Tobacco Straw Cores to Prepare Porous Carbon for Supercapacitor Applications

A large amount of tobacco straw residues is produced around the world every year. These tobacco straw residues are usually incinerated or landfilled directly, which cause environmental pollution and waste of resources. Therefore, it is necessary to find a green way to recycle these tobacco straw residues. Converting tobacco straw residues into biomass carbon materials for supercapacitor electrode materials is an appropriate way. In this study, tobacco straw core carbon (TSC) was obtained from tobacco straw core waste, which was carbonized directly in the tube furnace without N2. The tobacco straw core carbon had a higher specific surface area because of the self-activation of the H2O and CO2 in the carbonization. A variety of analytical instruments were used to characterize the prepared porous carbon. Herein, this work can provide new ideas for energy materials, and solve the problem of the disposal of tobacco straw residues. What’s more, it also can provide a sustainable development opportunity for tobacco farmers to alleviate poverty, dig potential and transform.