Sriwong, Chaval

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Sriwong, Chaval
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chaval.sr@kmitl.ac.th

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    Synthesis and electrochemical properties of activated lignite carbons-reduced graphene oxide nanocomposites symmetric supercapacitors
    (2024-08-15)
    Tuichai, Wattana
    ;
    Karaphun, Attaphol
    ;
    Phrompet, Chaiwat
    ;
    Chanlek, Narong
    ;
    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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    Dielectric and electrochemical properties of hybrid Pt nanoparticles deposited on reduced graphene oxide nanoparticles /poly (vinylidene fluoride) nanocomposites
    (2021-06-01)
    Karaphun, Attaphol
    ;
    Tuichai, Wattana
    ;
    Chanlek, Narong
    ;
    Sriwong, Chaval
    ;
    Ruttanapun, Chesta
    Nano-sized platinum (Pt) materials deposited on reduced Graphene Oxide (rGO) nanosheets (hybrid Pt-rGO nanoparticle) were prepared by the seed-mediated growing process using 20 wt% of Pt nanomaterials in rGO suspension. Dielectric properties of hybrid Pt-rGO nanoparticles/poly (vinylidene fluoride) nanocomposites (Pt-rGO/PVDF nanocomposites) were synthesized by a liquid–phase assisted dispersion and hot–pressing methods with different volume fractions (f) of hybrid Pt-rGO nanoparticle loading PVDF nanocomposites. The observed particle size of Pt nanomaterials deposits on rGO nanosheets was 5 nm. The dielectric constant (ε′) of Pt-rGO/PVDF nanocomposites was increased with increasing hybrid Pt-rGO nanoparticle. The volume fraction f<inf>Pt-rGO</inf> ≈0.0786 exhibited excellent ε′ ≈ 86 with very low loss tangent (tanδ) ≈ 0.021 at 1 kHz. High dielectric properties of Pt-rGO/PVDF composite should be ascribed to combination of the micro-capacitor and Maxwell–Wagner–Sillars (MWS) effects. Electrochemical properties of specific capacitances (C<inf>sc</inf>) and capacity retention of hybrid Pt-rGO nanoparticle electrode were investigated by the cyclic voltammetry and the galvanostatic charge-discharge. Interestingly, the hybrid Pt-rGO nanoparticle electrode displayed maximum C<inf>sc</inf> value of 169.8 F g<sup>−1</sup> at the current densities of 0.25 A g<sup>−1</sup>. This was due to the occurrence of various oxygen functional groups in the rGO- and Pt<sup>+</sup> ions as contributing to form of pseudo-capacitance in hybrid Pt-rGO nanoparticle.
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    The influence of annealing on a large specific surface area and enhancing electrochemical properties of reduced graphene oxide to improve the performance of the active electrode of supercapacitor devices
    (2021-02-01)
    Karaphun, Attaphol
    ;
    Phrompet, Chaiwat
    ;
    Tuichai, Wattana
    ;
    Chanlek, Narong
    ;
    Sriwong, Chaval
    Influence of annealing process on microstructure, large specific surface area and enhancing electrochemical properties to synthesize reduced graphene oxide (rGO) for the supercapacitor electrode was investigated. Thermal annealing process of rGO (rGO_An) was improved crystallinity and electrical conductivity. BET analysis of rGO_An sample exhibited the occurrence of large mesoporous and macrospores with a huge specific surface area of 672.1 m<sup>2</sup>/g and an average pore size of 46.2 nm, resulting the rGO_An sample activates more electrodes than rGO sample. Specific capacitance (C<inf>s</inf>) was affected by improving conductivity through annealing process with an excellent cycling stability after 750 cycles for GCD tests of 97.32%, which exhibited the highest value and an average energy density of 412.096 F g<sup>−1</sup> and 74.5 Wh kg<sup>−1</sup>, respectively at 1 A g<sup>−1</sup>. Thus, annealing process can occur with large mesoporous and macrospores pore improving the electrical conductivity and stability to be applied as an electrode in supercapacitor.