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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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Hydrothermal transforming phase structure and chemical composition of V2O5 for elevating electrochemical property of zinc ion batteries
(2024-05-01)
Triosod, Sureerat
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Phakkhawan, Authit
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Phumuen, Phatcharin
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Wanabut, Wassana
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Chanlek, Narong
V<inf>2</inf>O<inf>5</inf> was hydrothermally modified in NaOH or KOH solutions at 180 °C for 24 h. The NaOH-modified powders had a nanorod-like structure with a crystal structure matching Na<inf>2</inf>V<inf>6</inf>O<inf>16</inf>·nH<inf>2</inf>O. The TG/DTA results of Na<inf>2</inf>V<inf>6</inf>O<inf>16</inf>·nH<inf>2</inf>O powders show a mass reduction of 4.24 % at 300 °C, corresponding to n of 1.496. KOH-modified powders have large rods and irregular structures with a crystal structure matching KV<inf>3</inf>O<inf>8</inf>. Its TG/DTA spectrum shows a very small percentage change, just 0.37 % at 600 °C. Cyclic voltammetry (CV) curves of a Na<inf>2</inf>V<inf>6</inf>O<inf>16</inf>·nH<inf>2</inf>O cathode in a 2 M ZnSO<inf>4</inf> electrolyte exhibit higher oxidation and reduction current densities than those of pure V<inf>2</inf>O<inf>5</inf> and KV<inf>3</inf>O<inf>8</inf> electrodes.The best capacity of a Na<inf>2</inf>V<inf>6</inf>O<inf>16</inf>·nH<inf>2</inf>O electrode is 296.10 mAh g-1 at a current density of 50 mA g−1, which is higher than those of pure V<inf>2</inf>O<inf>5</inf> (102.90 mAh g-1) and KV<inf>3</inf>O<inf>8</inf> (91.07 mAh g-1) electrodes. EDS and XPS results reveal that the charge and discharge states involve de-insertion and insertion of Zn2+ ions out of/into the electrodes. Computational analysis of Zn intercalation into V<inf>2</inf>O<inf>5</inf>, Na<inf>2</inf>V<inf>6</inf>O<inf>16</inf>·nH<inf>2</inf>O, and KV<inf>3</inf>O<inf>8</inf> structures displays increasing electron density on neighboring V atoms, which explains the increasing V4+/V5+ ratio in the discharged state as evidenced by XPS spectra.
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Effect of GeI2 and GeBr2 incorporation on perovskite properties and performance of carbon-based perovskite solar cells
(2023-04-01)
Aunping, Namfon
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Kumlangwan, Pantiwa
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Towannang, Madsakorn
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Chanlek, Narong
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Kumnorkaew, Pisist
CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> (MAPbI<inf>3</inf>) film was prepared by a convective method, and its X-ray diffraction spectrum displays the tetragonal perovskite structure. GeI<inf>2</inf> and GeBr<inf>2</inf> powders dissolve poorly in a mixed dimethylformamide-dimethylsulfoxide (DMF-DMSO) solvent, but the introduction of 5 wt% 5-ammonium valeric acid iodide (5-AVAI) into the mixed DMF-DMSO solvent greatly promotes GeI<inf>2</inf> and GeBr<inf>2</inf> solubility. XRD spectra of the (5-AVAI)MAPbI<inf>3</inf>, MAGe<inf>x</inf>Pb<inf>1–x</inf>I<inf>3</inf>, and MAGe<inf>x</inf>Pb<inf>1–x</inf>Br<inf>2x</inf>I<inf>3–2x</inf> (x = 0.0625 and 0.125) films exhibit a tetragonal perovskite structure, but the film morphologies become rougher than that of the pristine MAPbI<inf>3</inf> film. Discontinuous islands are formed on MAGe<inf>x</inf>Pb<inf>1–x</inf>I<inf>3</inf> and MAGe<inf>x</inf>Pb<inf>1–x</inf>Br<inf>2x</inf>I<inf>3–2x</inf> (x = 0.125) films. X-ray photoemission spectroscopy (XPS) analysis detected the Ge element on all Ge-doped films. The best performance levels of the carbon-based hole transport layer-free MAGe<inf>x</inf>Pb<inf>1–x</inf>I<inf>3–x</inf> (x = 0.0625, η= 3.63%) and MAGe<inf>x</inf>Pb<inf>1–x</inf>Br<inf>2x</inf>I<inf>3–2x</inf> (x = 0.0625, η = 2.95%) perovskite solar cells are lower than that of the pristine MAPbI<inf>3</inf>–based perovskite solar cell (η = 5.28%). This is likely due to the increased surface roughness, pin-holes, isolated islands, and the decreased light absorbance of the Ge-doped films in comparison with the pristine MAPbI<inf>3</inf> film.
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Influence of SCN− moiety on CH3NH3PbI3 perovskite film properties and the performance of carbon-based hole-transport-layer-free perovskite solar cells
(2022-01-01)
Prasan, Primprapha
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Aunping, Namfon
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Chanlek, Narong
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Kumlangwan, Pantiwa
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Towannang, Madsakorn
CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> perovskite films were prepared via a hot-casting method using six different CH<inf>3</inf>NH<inf>3</inf>I, PbI<inf>2</inf> and Pb(SCN)<inf>2</inf> solutions. Surface morphology of perovskite films with low SCN− dopant levels (0.0625 M and 0.125 M Pb(SCN)<inf>2</inf>) showed smooth surfaces and large grain sizes. However, with the high SCN− dopant levels (0.1875 M and 0.25 M Pb(SCN)<inf>2</inf>), rough surfaces were produced with pinholes. The crystal of pure CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> (0 M Pb(SCN)<inf>2</inf>) film is a tetragonal perovskite structure. XRD spectra of all five Pb(SCN)<inf>2</inf> added films show the present of CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> films and the additional peak at 12.66°. Rietveld refinement analysis reveals that the Pb(SCN)<inf>2</inf> addition causes the second phase PbI<inf>2</inf> formation along with the tetragonal MAPbI<inf>3</inf> perovskite film rather than the CH<inf>3</inf>NH<inf>3</inf>Pb(SCN)<inf>x</inf>I<inf>3-x</inf> perovskite formation. The carbon-based hole-transport-layer (HTL)-free perovskite (from 0.0625 M Pb(SCN)<inf>2</inf> dopant) solar cell is the optimal ratio in generating a promising cell efficiency, 6.34%, with a good efficiency retention of 79.43% after 30 days of testing in comparison to a pure CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> (0 M Pb(SCN)<inf>2</inf> dopant) perovskite solar cell with an efficiency retention of only 26.92%. The great stability of the Pb(SCN)<inf>2</inf> added perovskite solar cells is attributed to the PbI<inf>2</inf> layer covered MAPbI<inf>3</inf> grains blocking oxygen and/or water molecules from degrading MAPbI<inf>3</inf> perovskite.
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Electrochemical mechanisms of activated carbon, α-MnO2 and composited activated carbon-α-MnO2 films in supercapacitor applications
(2021-12-30)
Tagsin, Patin
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Suksangrat, Pitphichaya
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Klangtakai, Pawinee
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Srepusharawoot, Pornjuk
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Ruttanapun, Chesta
Pure α-MnO<inf>2</inf> and activated carbon-MnO<inf>2</inf> (AC-MnO<inf>2</inf>) films coated on Ni foam by electrophoretic deposition were applied as a supercapacitor electrode. The specific capacitance of AC-MnO<inf>2</inf> films (155.03 F g−1) surpasses those of the pure AC (110.62 F g−1) and pure MnO<inf>2</inf> film in the 1 M NaOH electrolyte. EDX and XPS detect an increase in the Na content and the reduction of Mn4+ to Mn3+ on the discharged MnO<inf>2</inf> electrode (at 0.0 V), whereas a decrease in the Na content and the oxidation of Mn3+ to Mn4+ were obtained on the charged MnO<inf>2</inf> electrode (at 0.45 V). Computational simulation of the Na inserted α-MnO<inf>2</inf> structure displays the connection of Na to O atoms and the increasing electron density on Mn atoms. EDX of the charged AC-MnO<inf>2</inf> (at −1.0 V) film detects a rise in the Na and a fall in the O contents, but the discharged AC-MnO<inf>2</inf> film (at 0.0 V) shows a decrease in Na and increase in O contents. The AC-MnO<inf>2</inf> film could retain 82.29% of the initial specific capacity after 10,000 cycles. Four series-supercapacitor coin cell assembled from the AC-MnO<inf>2</inf> anode and MnO<inf>2</inf> cathode delivers a power density of 2.79 kW kg−1 and an energy density of 168.8 Wh kg−1.
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Preface
(2021-09-20)
Thammavintorn, Preecha
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Limkaisang, Viroj
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Charoenprakdee, Anek
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Seetawan, Tosawat
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Kimura, Kaoru
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Types A and D Trichothecene Mycotoxins from the Fungus Myrothecium roridum
(2019-07-01)
Lakornwong, Waranya
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Kanokmedhakul, Kwanjai
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Soytong, Kasem
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Unartngam, Arm
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Tontapha, Sarawut
Chromatographic separation of extracts from the fungal biomass of a plant pathogenic fungus, Myrothecium roridum, yielded 8 trichothecene toxins including 6 type D trichothecenes (1 - 6) and 2 type A trichothecenes (7 - 8). 6′,12′-Epoxymyrotoxin A (1) and 7′-hydroxymytoxin B (2) were new macrocyclic trichothecenes, while the other trichothecenes were identified as myrotoxin B (3), myrotoxin D hydrate (4), 2′,3′-epoxymyrothecine A (5), miotoxin A (6), and 2 trichothecenes lacking the macrocyclic lactone system, roridin L-2 (7) and trichoverritone (8). The structures of these mycotoxins were characterized using spectroscopic methods. The absolute configurations of 1 and 2 were determined by NOESY and a comparison of their experimental and calculated ECD spectra. Most of these mycotoxins (1 - 4 and 6) exhibited highly potent antimalarial activity against Plasmodium falciparum. They also showed strong cytotoxicity towards KB and NCI-H187 cell lines (IC <inf>50</inf> 0.60-112.28 nM), as well as the Vero cell line (IC <inf>50</inf> 1.50-46.51 nM).
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Effect of cell temperatures and flow-field patterns of bipolar plate electrodes on the performance of proton exchange membrane fuel cell by computational simulation
(2017-10-01)
Saraihom, Lirada
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Srimongkon, Kridsanapan
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Ruttanapun, Chesta
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Tangtrakarn, Apishok
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Faibut, Narit
The performances of fuel cell employing a bipolar plate with different gas-flow-field patterns for proton exchange membrane fuel cell (PEMFC) were simulated using higher-order polynomials (h-p) finite element method (h-p FEM). The patterns of each model were as follows: the straight pipe on both sides (Model 1), the serpentine flow-field for anode and the straight pipe for cathode (Model 2), the slotted serpentine for anode and the straight pipe for cathode (Model 3), and the serpentine on both sides (Model 4). It was found that as the cell temperature increased, the diffusion velocity of reactant gases and Maxwell-Stefan-diffusion coefficient of proton dramatically increased. The performance of PEMFC reached the highest value as the flow velocity of reactant gases and the diffusion coefficient of proton through membrane were optimized at the temperature of 80 °C. The most efficient flow-field pattern in this study is Model 2.
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P-Type optoelectronic and transparent conducting oxide properties of delafossite CuAl1/2Fe1/2O2
(2015-12-03)
Ruttanapun, Chesta
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Jindajitawat, Phumin
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Buranasiri, Prathan
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Harnwunggmoung, Adul
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Charoenphakdee, Anek
CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite was prepared using a solid-state reaction method to investigate its optical and electronic transport properties. CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> formed a hexagonal delafossite structure with an R3¯m space group. The positive Seebeck coefficient and the direct optical gap of 3.6 eV confirmed that the CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite in a p-type transparent conducting oxide. The fluorescence emission at 390 nm (green emission) confirmed that CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> has a direct transition band gap. Thermogravimetric analysis indicated a weight loss of 1.2%, caused by the intercalation of O atoms, which produced hole carriers from the different ionic radii at the B sites. The electric conductivity at room temperature was thermally activated, as predicted by the small-polaron hopping mechanism, with an activation energy of 75 meV and a charge transport energy of 61 meV. CuAl<inf>1/2</inf>Fe<inf>1/2</inf>O<inf>2</inf> delafossite exhibited p-type optoelectronic behavior and is a transparent conducting oxide, which may be crucial in the p-type photonic and electrode industries.
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A Flexible plastic-stainless steel dye-sensitized solar cell based on organic T-/T2 electrolyte
(2014-03-25)
Pimanpang, Samuk
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Towannang, Madsakorn
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Thiangkaew, Anongnad
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Maiaugree, Wasan
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Uppachai, Pikaned
SUMMARY: Flexible dye-sensitized solar cells (DSSCs) were fabricated using a TiO<inf>2</inf> film coated on stainless steel (TiO<inf>2</inf>/SS) as the working electrode and a Pt film coated on conductive plastic (Pt/plastic) as the counter electrode. Thin Pt film was deposited on conductive plastic specimens for four different deposition times (30, 60, 90 and 120s) using an electrochemical deposition process. Scanning electron micrographs of the resulting Pt films showed that Pt nanoparticles formed on conductive plastic. The DSSC characteristics were analyzed by illuminating light on the counter electrode. The performance of the cell with 30s of Pt deposition (30s-Pt) showed the highest DSSC efficiency, ~2.72%. Cell efficiency decreased with the duration of Pt deposition (or Pt thickness). This is attributed to the reduced transmittance through the thicker Pt films, which is supported by UV-visible spectroscopic measurements. © 2013 John Wiley & Sons, Ltd.

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