RECENT ADVANCES AND CHALLENGES OF CURRENT COLLECTORS FOR SUPERCAPACITORS

Global energy and environmental issues are driving the development of modern advances in efficient and environmentally friendly energy storage systems. Such systems must meet a range of requirements, which include high energy and power density, long service life, flexibility, industrial scalability, security and reliability. Progressive achievements in the field of energy storage are associated with the development of various kinds of batteries and supercapacitors. Supercapacitors are state-of-the-art energy storage devices with high power density, long lifespan, and the ability to bridge the power/energy gap between conventional capacitors and batteries/fuel cells. However, supercapacitors have limitations associated with low energy density, which can be solved by using various types of current collectors, since current collectors are one of the main massive components of supercapacitors. This review gives a complete understanding of the effect of current collectors on the actual performance and properties of supercapacitors. We reviewed current collectors based on carbon and metal-containing materials, and supercapacitor configurations to identify possible improvements in electrochemical performance in terms of specific capacitance, energy density, power density, service life and variability in their application

EFFECTIVENESS OF BIO-WASTE-DERIVED CARBON DOPING ON DE-ICING PERFORMANCE OF AN ELECTRICALLY RESISTANT CONCRETE

This paper proposes a modified carbon-based concrete filler composition, which can potentially be used as a self-de-icing pavement. Carbon fibers (CNFs), graphene-like porous carbon (GLC), and a CNF/GLC composite were developed to reinforce concrete with the aim to improve its electrical conductivity and mechanical properties. The effect of the CNF and GLC loadings on the electrical conductivity of the filled concrete was evaluated in a climatic chamber at temperatures simulating water-freezing conditions on a concrete road. The results show that even a negligible loading (0.2 wt.%) of concrete with CNF/GLC results in a dramatic decrease in its resistance when compared to the same loadings for CNF and GLC added separately. Depending on the number of fillers, the temperature of the modified concrete samples reached up to +19.8 °C at low voltage (10 V) at −10 °C, demonstrating the perspective of their heat output for anti-icing applications. Additionally, this study shows that adding 2.0 wt.% of the CNF/GLC composite to the concrete improves its compressive strength by 33.93% compared to the unmodified concrete

Investigations of Activated Carbon from Different Natural Sources for Preparation of Binder-Free Few-Walled CNTs/Activated Carbon Electrodes

In this study, we present another approach to fabricating high-performance supercapacitor electrodes by combining activated carbon particles with carbon nanotubes (AC/CNT). We synthesized activated carbon from diverse biomass sources using a carbonization process and chemical activation with KOH. By incorporating carbon nanotubes, we significantly augmented the electrode’s surface area, resulting in exceptional ion transport and a substantial increase in specific capacitance. Our investigation reveals that the optimized composition, 85:10:5 of AC, CNT, and conductive additive, achieved outstanding specific capacitance values, notably 125.6 F g−1 at 1 mV s−1 and 118 F g−1 at 1 A g−1, along with a maximum energy density of 4 Wh kg−1. Electrochemical impedance spectroscopy (EIS) further demonstrated the superior charge transfer capabilities of these electrodes, notably at a frequency range from 100 kHz to 10 mHz. Additionally, our research highlights the influence of different biomass precursors, such as apricot kernels, walnut shells, and rice husks, on the electrochemical behavior of these electrodes. Overall, this study provides valuable insights into the development of high-performance supercapacitors, emphasizing the potential of diverse biomass sources in optimizing electrode materials

EFFECT OF GRAPHENE OXIDE/HYDROXYAPATITE NANOCOMPOSITE ON OSTEOGENIC DIFFERENTIATION AND ANTIMICROBIAL ACTIVITY

This paper presents the fabrication and characterization of electrospun graphene oxide/calcium hydroxyapatite/polycaprolactone composite. Polycaprolactone is well-known for its excellent medical property and chemo-resistance. On the other hand graphene oxide (GO) and calcium hydroxyapatite (HAp) are both known for their superior biocompatibility, high mechanical properties, considerable electrical and thermal conductivity. Under current research GO and HAp were synthesized from an abundant bio-wastes material. As-prepared GO/HAp composite was dispersed in biodegradable polymer – polycaprolactone (PCL) in order to device a composite scaffold with the purpose to enhance osteogenic differentiation of osteoblasts for potential medical application. Synthesised composite was characterised using various chemo-physical methods. Biocompatibility was tested in the cell proliferation assay with preosteoblasts MC3T3-E1 cell line in order to identify any cytotoxic effect caused by its compounds. The bacteriostatic effect of GO was assessed using Staphylococcus aureus and Escherichia coli bacterial strains. Obtained GO/HAp/PCL composite scaffold can serve as a biologically compatible matrix for potential bone tissue regeneration with antimicrobial effect; provides an excellent biological compatibility for prospective application in medicine and clinical dentistry

Modified Activated Graphene-Based Carbon Electrodes from Rice Husk for Supercapacitor Applications

The renewable biomass material obtained from rice husk, a low-cost agricultural waste, was used as a precursor to synthesize a highly porous graphene-based carbon as electrode material for supercapacitors. Activated graphene-based carbon (AGC) was obtained by a two-step chemical procedure and exhibited a very high specific surface area (SSA) of 3292 m2 g−1. The surface morphology of the synthesized materials was studied using scanning and transmission electron microscopy (SEM, TEM). Furthermore, the AGC was modified with nickel hydroxide Ni(OH)2 through a simple chemical precipitation method. It was found that the most significant increase in capacitance could be reached with Ni(OH)2 loadings of around 9 wt.%. The measured specific capacitance of the pure AGC supercapacitor electrodes was 236 F g−1, whereas electrodes from the material modified with 9 wt.% Ni(OH)2 showed a specific capacitance of up to 300 F g−1 at a current density of 50 mA g−1. The increase in specific capacitance achieved due to chemical modification was, therefore 27%