Synthesis of PI-MWCNTs flexible electrode material loaded on carbon cloth and its capacitive performance

Metal-organic frameworks (MOFs) due to their porosity and well-defined structures are considered to be very promising electrode materials for the construction of high-performance supercapacitor (SC). In this paper, manganese-based metal-organic framework (Mn-MOF) were prepared on the surface of carbon cloth (CC) by a facile hydrothermal method. The morphology and structure of the electrode material were characterized by scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Its electrochemical studies show that the Mn-MOF electrode materials exhibit lower charge transfer resistance, the excellent specific capacitance of 433.5 mF/cm2 in 1.0 M Na2SO4 aqueous solution at the current density of 0.8 mA/cm2. It is noteworthy that the flexible electrode have excellent cycle stability and 105% capacitance retention even after 5000 cycles at a current density of 5 mA/cm2. The excellent electrochemical performance of Mn-MOF/CC flexible electrode materials can be attributed to its three-dimensional porous structure.

Non-stationary electrochemical synthesis of flexible binder-free hybrid electrode materials for supercapacitors

Nitric acid oxidation of activated carbon fabric in combination with calcination in at different temperatures was conducted to explore the influence of surface carbon-oxygen complexes on the performance of electrochemical capacitors fabricated with the carbon fabric. The performance of the capacitors was tested in 1 M within a potential range of and 0.6 V. The specific capacitance of the carbon was found to increase upon oxidation. Surface complex analysis using temperature programmed desorption showed that the double-layer capacitance was enhanced due to the presence of CO-desorbing complexes while -desorbing complexes exhibited a negative effect. The micropore resistance for ion migration was low for these carbons. The electrical connection resistance between the fabric and the backing plate as well as that between the carbon fibers accounted for the major proportion of the overall resistance and was shown to increase due to oxidation. A capacitance increase of more than 40% has been achieved, without increasing IR drop, by nitric acid oxidation followed by 450°C calcination that was shown to remove the majority of the -desorbing complexes while retaining the CO-desorbing complexes. © 2002 The Electrochemical Society. All rights reserved.

Influence of deposition temperature on physical and electrochemical properties of reduced graphene oxide electrode material for supercapacitor application

Carbon dots modified hydrange-shaped ZnCo(OH)F used as a flexible electrode for sensitive detection of dopamine and uric acid

Synthesis of PEDOT-modified graphene composite materials as flexible electrodes for energy storage and conversion applications

Hierarchical core–shell-like MnO2 nanostructures (NSs) were used to anchor MnO2 hexagonal nanoplate arrays (HNPAs) on carbon cloth (CC) fibers. The NSs were prepared by a novel one-step electrochemical deposition method. Under an external cathodic voltage of -2.0 V for 30 min, hierarchical core–shell-like MnO2-NS-decorated MnO2 HNPAs (MnO2 NSs@MnO2 HNPAs) were uniformly grown on CC with reliable adhesion. The phase purity and morphological properties of the samples were characterized by various physicochemical techniques. At a constant external cathodic voltage, growth of MnO2 NSs@MnO2 HNPAs on CC was carried for different time periods. When utilized as a flexible, robust, and binder-free electrode for pseudocapacitors, the hierarchical core–shell-like MnO2 NSs@MnO2 HNPAs on CC showed clearly enhanced electrochemical properties in 1 M Na2SO4 electrolyte solution. The results indicate that the MnO2 NSs@MnO2 HNPAs on CC have a maximum specific capacitance of 244.54 F/g at a current density of 0.5 A/g with excellent cycling stability compared to that of bare MnO2 HNPAs on CC (112.1 F/g at 0.5 A/g current density). We believe that the superior charge storage performance of the pseudocapacitive electrode can be mainly attributed to the hierarchical MnO2 NSs@MnO2 HNPAs building blocks that have a large specific surface area, offering additional electroactive sites for efficient electrochemical reactions. The facile and single-step approach to growth of hierarchical pseudocapacitive materials on textile based electrodes opens up the possibility for the fabrication of high-performance flexible energy storage devices.

This study investigates the mechanical performance and blast resistance of high-performance aramid, carbon, and ultra-high molecular weight polyethylene (UHMWPE) fiber fabrics, responding to the need for lightweight and flexible materials in anti-explosion containers for aviation and critical infrastructure. The experimental methodology integrated quasi-static and dynamic tensile tests to characterize the strain-rate effect, followed by near-field air blast tests on both single-material and hybrid multi-ply fabric specimens to analyze their dynamic response, failure modes, and overpressure attenuation. Key findings revealed that carbon fabric exhibited high stiffness but was strain-rate insensitive and susceptible to brittle perforation failure, whereas aramid and UHMWPE fabrics demonstrated strain-rate sensitivity, with UHMWPE showing superior ductility and energy absorption. The hybrid multi-ply configuration (A-C-U sequence) achieved the least amount of failure, effectively utilizing the wave impedance of aramid fabric for initial shock reflection, high stiffness of carbon fabric for stress homogenization, and plasticity of UHMWPE fabric for energy dissipation. Additionally, all fabrics attenuated peak overpressure by over 80%, with enhancement observed for increased thickness. The study concludes that the strategic layering of different fabrics creates a synergistic effect, mitigating the weaknesses of individual fabrics and establishing an effective design paradigm for advanced blast-resistant structures, further enhancing the protective performance.

Major concerns about the effects of increasing fossil fuel consumption on the environment and energy security have prompted the development of sustainable and environmentally-friendly energy conversion and storage technologies based on electrochemical processes (e.g. water electrolysers, batteries and supercapacitors). Electrode materials are a key component of these technologies, and high-performance electrode systems are essential for the realization of a clean-energy-based economy. Numerous efforts have been made to develop advanced electrode materials for energy conversion and storage applications. However, current electrode synthesis methods are usually energy-intensive, not environmentally friendly, difficult to scale, or costly to produce. This thesis aims to utilize electrode structure engineering to develop highperformance electrodes based on earth-abundant materials via low-cost, energy-efficient and green synthesis strategies. Further, the applications of these electrodes in various energy conversion and storage applications are explored. Nickel-iron oxides or hydroxides are considered promising electrocatalysts for the oxygen evolution reaction, featuring a high activity and long cycling life in alkaline solution. A room temperature, electroless method has been developed here to grow nickel-iron hydroxides on a nickel foam current collector. The activity of nickel foam for the oxygen evolution reaction can be remarkably enhanced by simply immersing the nickel foam in a ferric nitrate solution at room temperature. During this process, the oxidation of the nickel foam surface by ferric nitrate ions increases the near-surface concentration of hydroxide ions, which results in the in situ deposition of a highly active, amorphous nickel-iron hydroxide layer. This phenomenon is described in Chapter 2 of this thesis. Carbon cloth is a widely-adopted current collector for the fabrication of electrodes. A facile, two-step method has been investigated here to turn commercial carbon cloth into a high-performance electrode for zinc-air batteries. Mild acid oxidation followed by air calcination directly activate carbon cloth to generate uniform, nanoporous and superhydrophilic surface structures with optimized, oxygen-rich functional groups and dramatically increased surface area. This two-step-activated carbon cloth exhibits superior bifunctional oxygen electrocatalytic activity and durability. A rechargeable, flexible zinc-air battery using the activated carbon cloth as a binder-free, flexible air electrode yields a remarkably high peak power density, high flexibility, and good cycling performance, with a small charge-discharge voltage gap. This work is elaborated in Chapter 3. Cost-effective synthesis of large-scale, uniform electrode materials with high activity and cycling stability is challenging. In Chapter 4, a reaction environment confinement strategy for scalable and reproducible production of nanostructured materials is proposed. Nickel foam is simply immersed in metal nitrate aqueous solution, with the volume of solution per unit area of nickel foam kept very low. A precisely designed reactor with a spiral tunnel ensures the same width of solution on each side of the nickel foam. The reaction environment is confined to ensure reproducible and uniform synthesis of nanostructured materials across the Ni foam. This approach has the largest REAVC (ratio of electrode area to precursor volume consumption) value reported so far, 2.0 cm2 mL-1. The synthesized nickel-iron hydroxides/nickel foam electrodes with uniformity in both microstructure and electrochemical properties exhibit remarkable activity for both the oxygen evolution reaction and hydrogen evolution reaction. Manganese oxides are a class of promising electrode materials for high performance supercapacitors. However, not all types of manganese oxides with different phases are electrochemically active, and their crystal structures have a considerable effect on their capacitance. In Chapter 5, a facile strategy is developed for the transformation of manganese oxide from the orthorhombic to birnessite crystal structure. The product exhibits significantly enhanced electrochemical performance as a supercapacitor electrode. This work opens up new possibilities for changing the crystal structure of manganese oxides towards optimized properties in electrochemical applications. This thesis makes significant contributions to our understanding of electrode structure engineering, materials science and electrochemical energy conversion and storage through: (i) designing novel nanostructured nickel-foam-based electrode systems with high electrocatalytic activity towards water oxidation via a simple immersion strategy at ambient temperature; (ii) developing facile activation procedures to endow commercially available, inactive carbon cloth with oxygen-rich functional groups and high oxygen electrocatalytic activity; (iii) controlling ion diffusion in a confined zone for uniform deposition of active materials over large-size electrodes, electrodes useful for various electrochemical applications; (iv) probing the phase transformation of manganese oxides from orthorhombic to birnessite, a material with enhanced electrochemical performance; (v) investigating the growth mechanisms of these advanced electrode materials to understand the origin of their exceptional activity.

Application of biomass-derived flexible carbon cloth coated with MnO2 nanosheets in supercapacitors

All-flexible lithium ion battery based on thermally-etched porous carbon cloth anode and cathode

CuO induced effects on the electrochemical properties of (In2O3)1-xCuOx nanocomposites for supercapacitor flexible electrode materials

With the increasing water pollution, traditional treatments cannot sufficiently remove pollutants, thereby prompting the development of photocatalysts. In this study, ZnO–carbon cloth (CC) and spherical ZnO/CdSe–CC heterostructures with different CdSe loadings were synthesized using an ultrasonic-hydrothermal method on flexible CC. Z20CdSe–CC (ZnO with 20 mg CdSe loaded on CC) exhibited the best visible-light-responsive photocatalytic performance, with approximately 83.5% methylene blue reduced in 180 min. In addition, the degradation efficiency of Z20CdSe–CC was maintained at 70.9% after three cycles in relation to that of the ZnO powder. The synergistic effect of CdSe and CC not only effectively widened the light absorption range of ZnO/CdSe–CC but also further promoted the effective transfer of carriers and realized an efficient photocatalytic degradation process. Therefore, the ZnO/CdSe–CC photocatalytic material with CC as the flexible substrate exhibited high photocatalytic activity and stability in environmental remediation. This provides a design idea for the development of an efficient and flexible photocatalytic material in line with the concept of green chemistry.

In this study, nano-sized SnO2 decorated on carbon cloth (SnO2/CC) is prepared through a simple and facile solid method. The nano-sized SnO2 is uniformly distributed on the surface of carbon fibers in carbon cloth, providing sufficient free space to relieve volume expansion and reduce electrode pulverization during cycling. The as-prepared SnO2/CC as a flexible, self-supporting and additive-free anode electrode for sodium-ion/lithium-ion batteries (SIBs/LIBs) can demonstrate outstanding electrochemical performance. SnO2/CC after annealing at 350 °C (SC-350) as an anode for SIBs can deliver a reversible capacity of 0.587 mA h cm−2 at the current density of 0.3 mA cm−2 after 100 cycles. In addition, when cycling at 1.5 mA cm−2, SC-350 can maintain 1.69 mA h cm−2 after 500 cycles when used as LIB anode. These results illustrate that the as-prepared SnO2/CC can be a promising flexible anode material for flexible SIBs/LIBs and provide a simple and practical method for designing new flexible electrode materials.

Carbon fabrics coated with nickel film through alkaline electroless plating technique