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Microwave-activated reduced graphene oxide composite with hydrothermally treated corn husk activated carbon as an active electrode for high electrochemical performance in symmetrical carbon-based supercapacitor devices
(2026-07-01)
Srakaew, Khattiya
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Ratchayotee, Pornthip
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Janorat, Phattharawadee
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Phrompet, Chaiwat
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Kitiwan, Mettaya
This work applies microwaves for synthesizing reduced graphene oxide (rGO) and waste material corn husk activated carbon composites as active electrode materials for symmetric supercapacitors. The rGO is activated by microwave treatment and corn husk carbon by KOH in processed hydrothermal activation, followed by compositing at various weight ratios. Among all compositions, rGO:H_Corn_C (90:10) is reported with the best properties, with a specific surface area of 314.2 m2/g and a high specific capacitance of 1152 F/g at 0.1 A/g. The optimized composite also delivered increasing energy and power densities of up to 160 Wh/kg and 9.68 × 102 W/kg, respectively, within a 1 V operating window. In an experiment by assembling a symmetric coil cell supercapacitor, the device showed a specific capacitance of 142.23 F/g at 0.1 A/g, cycling stability with 98.8% capacitance retention after 1000 cycles of charge-discharge, and peak energy and power densities of 40.68 Wh/kg and 5.74 × 102 W/kg. Overall, the composite material with a high content of rGO and corn husk-derived activated carbon prepared by the hydrothermal method exhibits high-performance for the material in supercapacitor applications.
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Synthesis of ZIF-8 powders and their electrochemical role as a protective layer minimizing dendrite formation and elevating anode stability in Zn-ion batteries
(2025-12-01)
Chananil, Patompong
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Triosod, Sureerat
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Phumuen, Phatcharin
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Chanlek, Narong
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Kumnorkaew, Pisist
A Zn-based metal-organic framework (Zn-MOF) was synthesized via a solvothermal process using Zn(NO<inf>3</inf>)<inf>2</inf>·6H<inf>2</inf>O and 2-methylimidazole (2-Hmim) in ethanol at 120 °C for 24 h, yielding a crystalline structure consistent with ZIF-8, exhibiting a high surface area (1820.73 m2 g−1) and a large pore size (1.47 nm). The ZIF-8 powder was coated onto a Zn plate (ZIF-8@Zn) and evaluated as a Zn-ion battery anode, demonstrating significantly enhanced cycling stability, with a lifespan up to 200 h across all current densities, outperforming bare Zn (132, 49, 34, 36, and 20 h for 1–5 mA cm−2) in a 2 M ZnSO<inf>4</inf> electrolyte. Post-plating/stripping analysis revealed that ZIF-8@Zn maintained a smooth morphology, whereas bare Zn exhibited pronounced roughness and dendrite formation. Cross-sectional SEM images confirmed a swollen ZIF-8 layer with reduced Zn thickness at higher plating/stripping current densities, and XRD analysis detected Zn<inf>4</inf>SO<inf>4</inf>(OH)<inf>6</inf>·4H<inf>2</inf>O and Zn<inf>4</inf>SO<inf>4</inf>(OH)<inf>6</inf>·5H<inf>2</inf>O byproducts on both electrodes. The ZIF-8@Zn| |V<inf>2</inf>O<inf>5</inf> full-cell exhibited superior capacity (314.03 vs. 251.75 mAh g−1 at 100 mA g−1) and long-term stability, with a 22.71 % capacity increase after 1000 cycles, in contrast to an 11.52 % reduction in the Zn| |V<inf>2</inf>O<inf>5</inf> cell, highlighting ZIF-8@Zn's potential for stable Zn-ion batteries.
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Investigating the High Electron Mobilities and Transport Scattering Processes in 2D Non-Van Der Waals Bi2O2Te Nanosheet Films
(2025-11-01)
Chomngam, Sasithorn
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Pimanpang, Samuk
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Ruttanapun, Chesta
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Rujisamphan, Nopporn
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Thongnum, Anusit
Bismuth oxytelluride (Bi<inf>2</inf>O<inf>2</inf>Te) nanosheets, a 2D non-van der Waals (2D-nvdW) semiconductor, has exceptionally high carrier mobilities, between 496 and 584 cm2V−1s−1 at room temperature (RT). Its numerous potential applications in multifunctional electronic devices have sparked much research interest. However, comprehensive explanations of the high RT mobilities and transport scattering processes in the Bi<inf>2</inf>O<inf>2</inf>Te nanosheet films are still sought. Herein, measured mobility data, between 5000 and 54,074 cm2V−1s−1 at 2 K and 125–584 cm2V−1s−1 at 300 K, are examined and modeled considering several scattering sources, including ionized impurities, longitudinal optical (LO) phonon, and electron–electron interactions. The total mobility based on three scattering mechanisms provided good quantitative agreement with the experimental results from thicknesses ranging from 21.0 to 55.0 nm. Ionized impurity scattering limits mobility at temperatures lower than 50 K, but LO phonon and electron–electron scatterings dominate at temperatures between 50 and 300 K. When the thickness decreases to 21.0 nm, electron-electron scattering strength becomes stronger and the RT mobility drops to 125 cm2 V−1s−1. These findings advance the knowledge of the charge transport mechanisms that underlie the Bi<inf>2</inf>O<inf>2</inf>Te nanosheet and provide more details for other 2D-nvdW and 2D semiconductors.
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The Impact of Incorporating Reduced Graphene Oxide Quantum Dots into KOH Electrolyte on the Electrochemical Performance of Supercapacitors Using Sugarcane Bagasse Active Electrodes
(2025-09-30)
Panturotai, Kuwalai
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Sriwong, Chaval
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Ruttanapun, Chesta
This study used reduced graphene oxide quantum dots (rGO-QDs) to enhance the ionic conduction and specific capacitance of the sugarcane bagasse carbon active electrode in a supercapacitor. The rGO-QDs solution was mixed with the KOH electrolyte at 0.5, 1.0, 3.0, and 5.0% by weight (rGO-QDs-X%/6M-KOH). The sugarcane bagasse-activated carbon (SAC) was prepared from sugarcane bagasse (SB) waste through activation by annealing in an argon atmosphere and ground in a high-speed three-dimensional (3-D) ball mill (AC3D-SAC). The rGO-QDs were synthesized and verified by high-resolution transmission electron microscopy (HRTEM), which showed that the size of the rGO-QDs was less than 10 nm. Raman spectroscopy displayed peaks of the D-band and G-band. The rGO-QDs-3%/6M-KOH electrolyte exhibited the highest ionic conductivity, 26 mS/cm. The AC3D-SAC active carbon had a specific surface area of 915.57 m2/g. The active electrodes made with AC3D-SAC and rGO-QDs-3%/6M-KOH for the half-cell electrode showed the highest specific capacitance of 176.83 F/g at 0.5 A/g. The working electrode symmetric supercapacitor coin cell device, using the rGO-QDs-3%/6M-KOH electrolyte, achieved a maximum specific capacitance of 54.53 F/g at 0.5 A/g. These results were twice as high as those with the KOH electrolyte alone. The efficiency retention of the coin cell dropped to 90% after 5000 cycles. The supercapacitor demonstrated impressive electrochemical performance with high ionic conduction and capacitance, thanks to the rGO-QDs/6M-KOH electrolyte and the large surface area of the AC3D-SAC active carbon. The findings confirmed that adding rGO-QDs to the KOH electrolyte improved the electrochemical performance of the symmetric supercapacitor device.
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A flow-circulation system incorporating a PVP-BiOBr@rGO assembly for simultaneous degradation and detection of oxytetracycline in fish farm wastewater
(2025-05-27)
Teerasong, Saowapak
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Suknakhin, Nichakarn
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Sonsaket, Thanamat
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Teerasong, Wanatchaporn
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Ruttanapun, Chesta
This work focuses on developing a new flow-circulation system for simultaneous detection and degradation of oxytetracycline (OTC) in fish farm wastewater to address a need for antibiotic abatement in wastewater treatment. Polyvinyl pyrrolidone capped bismuth oxybromide assembled with a reduced graphene oxide (PVP-BiOBr@rGO) photocatalyst was solvothermally synthesized and characterized. The prepared photocatalyst exhibited a morphological flower-like structure with a high surface area, 47.59 m2 g−1. Its band gap energy was 2.93 eV. A ternary PVP-BiOBr@rGO composite showed lower charge recombination than its pure form. PVP-BiOBr@rGO was filled inside a catalyst column of a flow system, with a spectrophotometer at the column end. Wastewater was continuously transported through the column and OTC spectrophotometrically examined during its degradation. The wastewater was recirculated until the OTC concentration was minimized. This system achieved 90.3% degradation of OTC within 180 min. The catalyst column could be regenerated for 2 cycles. The proposed flow system offers the advantages of ease of use, inline operation, and real-time sensing. This highlights a potential for real-world sustainable wastewater treatment applications.
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Effect of rGO nanosheet loading in SiO2/rGO hybrid nanocomposites for enhancing optoelectrical, physical, and electrochemical properties
(2025-05-01)
Khammahong, Sunisar
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Phrompet, Chaiwat
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Ruttanapun, Chesta
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Sriwong, Chaval
In this study, silicon dioxide nanoparticles (SiO<inf>2</inf>NPs) mixed with reduced graphene oxide nanosheets (rGONS) and hybrid nanocomposites (S/rGOHNCs) were synthesized to study the opto-electrical, physical and electrochemical properties. S/rGOx%HNCs samples with rGONS at various loadings (10, 30, 50, and 70 wt%) were prepared SiO<inf>2</inf>NPs and rGONS suspensions in ultrasonication process by conventional heating. The SiO<inf>2</inf>NPs, rGONS and S/rGOx%HNCs were characterized and properties confirmed by XRD, Raman spectroscopy, FT-IR spectra, UV–Vis, SEM, EDX and TGA techniques. The electrical conductivity carrier concentration, energy gap, and dielectric constant increased with rGONS loading. The S/rGO30HNCs exhibited the highest thermal conductivity, 0.7 W/m·K, and Vickers microhardness, 41.0 HV. The value of electrochemical capacity of S/rGO70HNCs, 66.95 F/g, was due to the appropriate ratio of rGONS and SiO<inf>2</inf>NPs which significantly contributed to increasing redox reaction. The findings offered SiO<inf>2</inf>NPs mixed rGONS hybrid nanocomposites with enhanced optoelectrical (electrical, optical, dielectric), physical (mechanical, thermal) and electrochemical properties.
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Fabrication, optical and ion conduction properties of reduced graphene oxide quantum dots and application in electrolyte supercapacitor devices
(2025-05-01)
Seesan, Tanatchaya
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Sriwong, Chaval
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Ruttanapun, Chesta
Reduced graphene oxide quantum dots (rGO-QDs) were synthesized via the hydrothermal method and characterized for their structural, optical, and ion conduction properties. Raman spectroscopy confirmed a low defect density (I<inf>D</inf>/I<inf>G</inf> ratio: 0.91), while X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed reduced interlayer spacing and particle sizes (∼4.14 nm), indicative of quantum confinement effects. Optical analysis demonstrated tunable photoluminescence and strong absorption, confirming their quantum dot nature. Electrochemical impedance spectroscopy (EIS) highlighted enhanced ionic conductivity and reduced internal resistance in supercapacitor devices utilizing KOH/rGO-QDs electrolytes, improving specific capacitance and ion transport. These results establish rGO-QDs as promising materials for optoelectronics and energy storage applications, particularly in high-performance supercapacitors.
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Enhancing electrochemical properties of an activated bamboo carbon-based supercapacitor with reduced graphene oxide nanocomposites through pulverizing and mixing in a 3-D high-speed ball mill
(2025-04-01)
Srichaiprapha, Kitima
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Ruttanapun, Chesta
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Sriwong, Chaval
Bamboo-activated carbon (AC-BBC) achieved improved electrochemical properties by compositing it with reduced graphene oxide (rGO) at 1, 3, 5, and 7% weight (wt%). The AC-BBC samples were prepared by annealing bamboo carbon (BBC) powder and a KOH mixture through flowing argon at 900 °C. It was pulverized and mixed using high-speed three-dimensional (3-D) ball milling. rGOx%/3D-AC-BBC (x = 1, 3, 5, and 7 wt%) samples, which are referred to as AC-BBC composites with x% rGO ground by 3-D ball milling, were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy techniques. Analysis using scanning electron microscopy (SEM) and specific surface area (SSA) revealed that the rGO5%/3D-AC-BBC sample exhibited the highest specific surface area (SSA), 2239.80 m²/g, with an average pore size of 2.22 nm. Half-cell electrodes had the greatest specific capacities, 301.80 F/g at 0.5 A/g. The symmetric supercapacitor coil cell device showed a capacitance of 85.93 F/g, an energy density of 11.93 Wh/kg, and a power density of 49.56 W/kg. The efficiency retention was reduced to 96.76% after 10,000 cycles. This manuscript presents a high-performance rGO5%/3D-AC-BBC material that can be used for active electrodes to enhance electrochemical properties, making them suitable for electric double-layer capacitor (EDLC) applications.
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Development of functional construction materials from cement–reduced graphene oxide composite capable of generating electricity with improved mechanical strength
(2024-09-01)
Sintusiri, Jirapan
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Hongsrichan, Pemika
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Boonsri, Phanupong
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Tongjune, Phitthayathon
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Sriwong, Chaval
In this work, we have developed a functional construction material from a cement material that can scavenge mechanical energy from surrounding environment into electricity. An energy harvesting device called “a triboelectric nanogenerator (TENG)” is fabricated from the cement–reduced graphene oxide (rGO) composite to convert mechanical energy into electrical power. The incorporation of rGO in cement is found to enhance the electrical output of the TENG through space charge polarization, resulting in the increase in triboelectric charge density. The maximum power density achieved from the cement–rGO composite TENG is 1.72 W/m2, which is six times greater than that of the unmodified cement TENG. Additionally, rGO improves the compressive strength of the cement composite by up to 50%. This enhancement is attributed to the large specific surface area of rGO, which creates nucleation sites, resulting in increased crystallization of cement hydration products. The findings of this work highlight the promising prospects for the development of functional construction material for smart energy building with improved mechanical strength. Graphical abstract: (Figure presented.)
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Synthesis and electrochemical properties of activated lignite carbons-reduced graphene oxide nanocomposites symmetric supercapacitors
(2024-08-15)
Tuichai, Wattana
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Karaphun, Attaphol
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Phrompet, Chaiwat
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Chanlek, Narong
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Swatsitang, Ekaphan
Ultra-fast chargeable or rechargeable symmetric carbon-based supercapacitors (SCSs) with high capacity, inexpensive, and non-flammability have attracted much attention for electronics and energy storage devices. However, improving both high redox reaction and ion transport/diffusion processes by enhancing high energy storage performance and rapid ion/electron transport SCSs electrode materials remains challenging. Herein, we presented a successful preparation of activated lignite carbons-reduced graphene oxide (ALC-rGO) nanocomposite (NCp) with the ALC:rGO ratio of 80:20 wt% by a one-pot hydrothermal for high electrochemical performance. Importantly, the matrix of ALC-rGO NCp was primary amorphous carbon with hexagonal graphitic layers and pore structures of plentiful micropores and mesopores. Remarkably, the ALC-rGO NCp electrode exhibited a maximum specific capacitance (C<inf>sc</inf>) of 152.12 F/g at 0.5 A/g. Interestingly, the SCSs-ACL-rGO device could illustrate a good performance at a potential voltage of 1.8 V with C<inf>sc</inf> of 50.90 F/g at 1 A/g and capacity retention of 96.0 % at 5 A/g after 2,000 cycles GCD test.

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