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Electrochemical performance of Bi2Te3 heterostructure thin film and Cu7Te4 nanocrystals on undoped and In3+-doped WO3 films for energy storage applications
(2020-05-01)
Buathet, Supitchaya
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Simalaotao, Kodchakorn
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Reunchan, Pakpoom
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Vailikhit, Veeramol
;
Teesetsopon, Pichanan
We demonstrated the synthesis of undoped and In3+-doped WO<inf>3</inf> as an electron acceptor for energy storage applications, by utilizing the electrochemical S2− insertion/extraction process at the heterostructure of rhombohedral Bi<inf>2</inf>Te<inf>3</inf> thin films and hexagonal Cu<inf>7</inf>Te<inf>4</inf> nanocrystals. The cyclic voltammetry of heterostructured electrodes with and without In3+ doping both showed Faradic pseudo-capacitance behavior based on the oxidation and reduction processes. The largest exchange current density of 3.43 mA/cm2 was obtained for the heterojunction-structured-Bi<inf>2</inf>Te<inf>3</inf> thin films and Cu<inf>7</inf>Te<inf>4</inf> nanocrystals with In3+ doping in the WO<inf>3</inf> electrode. This implies more favorable hydrogen evolution reaction kinetics and higher electrocatalytic activity at the anode. The highest specific capacity of 90.2 mA h/g was obtained at a scan rate of 10 mV/s, with the power density reaching 1.7 kW/kg at the highest energy density value of 18.85 Wh/kg for the In3+-doped electrode. The overall results revealed the inherent properties of the new electrode materials, as well as their potential use in energy storage devices or in future electrochemical energy conversion and storage applications involving hydrogen (or oxygen) evolution reactions.
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Structural and electrochemical studies of undoped and In3+-doped co-binary Cu2-xTe and Bi2Te3 thin films for aqueous Na–S batteries
(2019-10-01)
Sreerung, Rawita
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Raknual, Duanghatai
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Kitisripanya, Nareerat
WO<inf>3</inf> electrodes coated with co-binary Cu<inf>2-x</inf>Te and Bi<inf>2</inf>Te<inf>3</inf> thin films were fabricated for sodium-sulfur (Na–S) batteries. Film fabrication was controlled by adjusting the pH of the solution and the indium doping concentration. The phases of orthorhombic CuTe and hexagonal Cu<inf>2</inf>Te with rhombohedral Bi<inf>2</inf>Te<inf>3</inf> were formed on the WO<inf>3</inf> electrode. After In3+ doping, In3+ ions act as Frenkel defects in the Cu<inf>2-x</inf>Te structure. This indicated that In3+ ions are located at interstitial sites in the Cu<inf>2-x</inf>Te structure with higher defect creation energy. Furthermore, more interconnected-like nanoparticles and reduced porosity were observed, thereby indicating that indium segregation with grain boundaries presented and contributed to an enhancement of the surface mobility, nucleation density, and a smoother surface. For electrochemical characteristics, a polysulfide solution was used as a redox electrolyte for ion transport. Optimization of the pH and indium concentration attributed to improve the exchange current density (J<inf>0</inf>) and time responses for the colored and bleached states because of faster movement of Na+ and S2− ions during inter/de-intercalation. Furthermore, optimization of the electrode by adjusting the pH and doping with indium is advantageous for both Na–S and rechargeable batteries because of long life cycle, reasonably high power and energy density of 306 W/kg and 9.35 Wh/kg, respectively. The highest specific capacity (C<inf>s</inf>) values of the charge and discharge cycles for In3+-doped electrodes are ∼ 21 and 19 mAh/g, respectively with the coulombic efficiency approximates 100% (average value of ∼96%). This approach may provide a general path for the fabrication of undoped and In3+-doped co-binary Cu<inf>2-x</inf>Te and Bi<inf>2</inf>Te<inf>3</inf> films on WO<inf>3</inf> electrodes and may increase our knowledge regarding Na–S batteries for further performance improvement.
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Effective properties of undoped and Indium3+-doped tin manganese telluride (Sn1 − xMnxTe) nanoparticles via using a chemical bath deposition route
(2017-06-09)
Boon-on, Patsorn
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Tubtimtae, Auttasit
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Vailikhit, Veeramol
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Teesetsopon, Pichanan
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Choopun, Supab
Tin manganese telluride nanoparticles (Sn<inf>1−x</inf>Mn<inf>x</inf>Te NPs) were first synthesized on a niobium pentoxide (Nb<inf>2</inf>O<inf>5</inf>) film using a chemical bath deposition (CBD) route. An individual particle size before and after indium (In3+) doping of ∼70–150 nm was investigated with stoichiometric formation of the SnMnTe phase. Furthermore, a cubic or rocksalt structure of the Sn<inf>0.938</inf>Mn<inf>0.062</inf>Te phase was also kept incorporated in the structure. The plotted energy band gaps for undoped and In3+-doped samples were 2.17 and 1.83 eV, respectively. The reduction of photoluminescence (PL) spectra after In3+ doping, while the indium dopant acted as a trap state incorporated in Sn<inf>1−x</inf>Mn<inf>x</inf>Te NPs, showed enhanced charge separation and reduced charge recombination, which resulted in a higher charge density trapped in the conduction band of Nb<inf>2</inf>O<inf>5</inf> and was also confirmed by the result of anodic peaks in the cyclic voltammetry. These results suggest new possibilities in optoelectronic and electrochemical devices.

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