Asymmetric Supercapacitor Based on Biomass-Derived Carbon Electrodes Functionalized with NdFeB.

Medium-temperature fluoroalkylation of microporous activated carbons (ACs) with 1,1,1,2-tetrafluoroethane is presented. Supercapacitor (SC) electrodes based on the fluoroalkylated ACs showed enhanced specific capacitance and high specific energy in electrolytes, either aqueous potassium hydroxide solution or tetraethylammonium tetrafluoroborate-acetonitrile solution. We found the largest increase in the specific capacitance, up to 89 F g–1, and in the specific energy, up to 7.5 Wh kg–1, at the voltage of 1.5 V. The specific capacitance of the SC electrode based on the sample prepared at 350 °C increases by a factor of ~ 2–3 × for certain scan rates in the organic electrolyte. The fluoroalkylated ACs have good electrochemical stability in the tested model systems. We associate the registered enhanced SC parameters with an increase in the total fluorine content and high specific surface areas of the carbon electrode materials. The surface “isolated fluorine” formed during fluoroalkylation at 300–400 °C ensures the production of improved electrode materials for SC applications. Fluoroalkylation is a simple and cost-effective method of improving the specific capacitance of carbon-based SC electrodes.

Corn-straw-converted activated carbons with tunable porosity and N/O functionalities as high-performance supercapacitors electrode at commercial-level mass loading

Hierarchical CuCo2S4@NiMn-layered double hydroxide core-shell hybrid arrays as electrodes for supercapacitors

Polyaniline modified graphene and carbon nanotube composite electrode for asymmetric supercapacitors of high energy density

Developing energy storage systems has become a significant focus in supporting advancing renewable energy technologies and electric vehicles. Supercapacitors are a critical device in this endeavor, known for their high capacitance and low internal resistance. Although carbon-based supercapacitors have been widely used, they have low energy density. This research addresses the development of activated carbon (AC) and polyaniline (PANi) composite-based supercapacitors to improve the performance of energy storage devices. AC/PANi composites were synthesized in various ratios of (20:80)%, (50:50)%, and (80:20)% using in-situ polymerization method. Supercapacitor electrodes were prepared by mixing AC/PANi composite, acetylene black, and polyvinylidene fluoride (PVDF) with a mass ratio of (80:10:10)%. Furthermore, coin-type supercapacitor cells were assembled using AC/PANi composite electrodes, 1 M Et4NBF4 electrolyte, and polypropylene separator. Supercapacitor performance was evaluated using Cyclic Voltammetry (CV) methods. The results of FTIR analysis showed that the AC/PANi composite was successfully synthesized, with absorption peaks corresponding to the characteristics of AC and PANi. X-ray diffraction patterns showed that the AC/PANi composite exhibited amorphous properties. The CV test results show that the coin cell based on the AC/PANi composite (20%:80%) indicates the highest performance with significant specific capacitance. Thus, supercapacitor electrodes based on the AC/PANi composite show potential as active materials for supercapacitor devices.

Ultrasonically dispersed multi-composite strategy of NiCo2S4/Halloysite nanotubes/carbon: An efficient solid-state hybrid supercapacitor and hydrogen evolution reaction material

A novel solid-state fractionation of naphthenic acid fraction components from oil sands process-affected water

Two-dimensional titanium carbide (MXene)-wrapped sisal-Like NiCo2S4 as positive electrode for High-performance hybrid pouch-type asymmetric supercapacitor

Hierarchically porous activated carbons (ACs) derived from apricot shell (AS), which is a low-cost and abundant carbon source from a renewable and sustainable biomass waste, were prepared by a green and facile approach via carbonization followed by steam activation and applied to electrodes for symmetric supercapacitors (SCs). The as-obtained AC possessed large surface area and developed porosity with hierarchical pore texture, leading to the specific capacitance of 38.3 F g−1 for an AC//AC symmetrical SC in 20 wt% H2SO4 aqueous electrolyte. Moreover, the assembled AC//AC SC exhibited superior cycling life stability with 99% retention after 6000 cycles at 5 A g−1. These results demonstrate that the present facile, low-cost, and environmentally friendly synthetic strategy for hierarchical ACs from AS can promote the utilization and conversion of AS to high value-added industrial products as well as commercial applications in energy storage devices.

Revealing the causes of degradation of an asymmetric ionic liquid supercapacitor with a composite polyaniline/carbon electrode

Metal–organic frameworks (MOFs) have gained significant attention as potential supercapacitor electrodes due to their high surface area, tunability, and well-defined porosity. However, their application is often limited by low capacity, poor electrical conductivity, and weak substrate adhesion, as observed in zeolitic imidazolate framework-67 (ZIF-67). To address these limitations, this study investigates the effect of nickel incorporation into ZIF-67, aiming to enhance its electrochemical performance. A series of hybrid-MOFs, denoted as ZIF-67 : Ni (1 : X), were synthesized via a simple solution-phase method at room temperature by varying the nickel content. Nickel was introduced to facilitate faster redox reactions and improve ion transport, thereby enhancing charge storage capability. The optimized ZIF-67 : Ni (1 : 2) electrode exhibited a high specific capacity of 161.2 mA h g−1 at 1 A g−1, with a capacity retention of 74.6% after 5000 charge–discharge cycles, outperforming pristine ZIF-67 and other nickel-mixture variants. The improved electrochemical performance is attributed to the enhanced porous structure, which increased active site accessibility and reduced charge transfer resistance. Furthermore, an asymmetric supercapacitor device assembled using ZIF-67 : Ni (1 : 2) as the positive electrode and activated carbon (AC) as the negative electrode (ZIF-67 : Ni (1 : 2)//AC) demonstrated a cell capacity of 44.6 mA h g−1, a specific energy of 36.97 W h kg−1, and a specific power of 416.3 W kg−1 at 0.5 A g−1. Notably, the device exhibited excellent cycling stability, retaining 99.8% of its capacity after 10 000 cycles at 10 A g−1. These findings highlight the potential of multi-metallic interactions in enhancing the electrochemical performance of ZIF-67-based MOFs, offering valuable insights for the development of high-performance supercapacitor electrodes.

This work aims to use the electro‐active materials for energy storage application from the waste raw material source, readily and indigenously available materials. Nowadays, the use of waste sources to prepare electro‐active materials for energy storage applications is trending due to their low‐cost, high availability, reduced environmental problems, and so forth. In this direction, Polyaniline (PANI) is prepared using a MnO2 oxidant collected from waste Zn‐C cells. PANI displayed a compact and interconnected granular morphology with a surface area (39 m2 g−1), pore volume (0.19 cm3 g−1), and pore diameter (2.2 nm). Activated carbon (AC) has a surface area (860 m2 g−1), pore volume (199 cm3 g−1), and pore diameter (1.2 nm) is purchased locally. FT‐IR, XRD, and EDAX spectra support the formation of polyaniline salt with a small amount of Mn and Zn. The asymmetric cell is constructed using a PANI as a positive electrode and carbon as negative electrode material. The cell (PANI//AC) shows a high specific capacitance of 157 F g−1 at a current density of 5 mA cm−2. The cell offers a cycle life stability of 5000 cycles with a coulombic efficiency of 93% at a current density of 10 mA cm−2.

Activated carbon (AC) is one of the most promising active materials for high-performance supercapacitors (SCs) owing to its high specific surface area and theoretical specific capacity. In this study, oil palm empty fruit bunches (EFBs), which are agricultural residue, are employed as a precursor to produce AC using a series of cleaning, carbonization, and chemical activation processes. The as-produced AC has a specific surface area of 2774 m2/g, which is very high among AC produced from biomass materials. To enhance the performance of SCs, the AC is modified by nitrogen doping. The specific capacities of AC and nitrogen-doped AC are found to be 182 to 217 F/g, respectively, at a current density of 0.5 A/g in 6 M KOH aqueous electrolyte. We demonstrate that agricultural waste can be processed into AC with a high specific surface area for SC applications.

In this study, we successfully fabricated a composite sheet comprising bacterial cellulose (BC) and polyaniline (PAN), integrated with activated carbon (AC), to produce electrodes in a supercapacitor. The electrical conductivity level can be adjusted by adding AC into the composite. FTIR revealed hydrogen bonding interactions between the -OH groups of the bacterial cellulose and the -NH groups of the polyaniline. The XRD pattern showed the characteristic peak of activated carbon. The SEM showed that PAN was filled into the porous network of the bacterial cellulose. The AC was randomly distributed onto the composite’s surface. The composite was thermally stable up to 200 °C. The electrical conductivity was reported to be 1.5–3.5 S/m when AC was added from 0.2 to 1 wt%. Furthermore, the specific capacitances (Cs), energy densities (Es), and power density (P) were typically reported to be 30–70 F/g, 4–11 Wh/kg, and 400–700 W/kg, respectively. Moreover, the optimization of the activated carbon ratio led to a reduction in the charge transfer resistance (Rct), as demonstrated by a Nyquist plot analysis, thereby enhancing electrical conductivity. Overall, the bacterial cellulose and polyaniline composite sheet, incorporating activated carbon, exhibited excellent properties, making it a promising candidate for bioelectrode supercapacitor applications in the near future.

Activated carbon- supported Vanado-nickelate (IV) based hybrid materials for energy application