1. Utilizing the built-in electric field of pn heterojunction to spatially separate the photogenerated charges in C, N co-doped Co3O4/CdS photocatalysts
Tingzhen Chen, Chengwu Yang, Saravanan Rajendran, Montree Sawangphruk, Xinyu Zhang, Jiaqian Qin
Fuel, 2023, 331, 125594
Abstract:  As one of the most effective strategies for the storage and utilization of solar energy, the development of photocatalytic technology has received extensive attention. The core work, the design and modification of photocatalysts, is very significance. Herein, we prepared C, N co-doped Co3O4 (CN-CoO) by a simple method and composited it with CdS to form CN-CoO/CdS p-n type heterojunctions. The prepared materials are characterized by numerous tests, such as XRD, SEM, TEM, XPS, and photoelectrochemical measurement. Due to the excellent electrochemical performance of CN-CoO and the built-in electric field in CN-CoO/CdS, the efficient separation of photogenerated charges is realized. Compared with CdS (1.11 ns), the average carrier lifetimes of the 15%CN-CoO/CdS (1.63 ns) is prolonged, which enhances photocatalytic hydrogen evolution activity of the composite materials. The hydrogen evolution rate of the optimal 15%CN-CoO/CdS is 6.78-fold greater than that of pristine CdS, and is as high as 64.36 mmol·g−1·h−1. Meanwhile, the 15%CN-CoO/CdS exhibits outstanding chemical stability after cyclic hydrogen production experiment for 30 h, and its apparent quantum efficiency (AQE) reaches 27.47% under monochromatic light at 405 nm. In addition, the formation process and photocatalytic hydrogen evolution mechanism of the CN-CoO/CdS p-n type heterojunctions are analyzed and discussed. This work provides a new idea for the construction of efficient photocatalytic heterojunctions through the modification and combination of semiconductors.

2. Twin boundaries boost the hydrogen evolution reaction on the solid solution of nickel and tungsten

Jiuchao Tang, Jingjing Niu, Chengwu Yang, Saravanan Rajendran, Yongpeng Lei, Montree Sawangphruk, Xinyu Zhang, Jiaqian Qin
Fuelมม 2022ม 330ม 125510
The development of cost-effective electrocatalysts to produce high-purity hydrogen by electrochemical water splitting is critical to addressing resource and environmental problems. Theoretically, NiW materials are considered to be an excellent HER electrocatalyst. However, current NiW catalysts for HER are not satisfactory. Herein, the NiW solid solution with twin boundaries is successfully fabricated by facile electrodeposition on copper sheet. As compared with Ni, the NiW-0.6A catalyst shows enhanced HER activity in 1 M KOH with the overpotential of 98 mV at 10 mA/cm2. Besides, NiW-0.6A exhibits excellent stability for 100 h at 20 mA/cm2. The excellent HER performance of NiW-0.6A may be attributed to the intrinsic catalytic activity and the defective twin boundaries exposing many active sites. This work could provide feasible suggestions for the design of efficient and high-performance NiW electrocatalysts for HER process..

3. Li-ion batteries of Ni-rich lithium nickel cobalt aluminium oxide coupled with high-energy lithiophilic anode
Poramane Chiochan, Phansiri Suktha, Nutthaphon Phattharasupakun, Salatan Duangdangchote, Montakan Suksomboon, Worapol Tejangkura, Montree Sawangphruk
SCIENCE SOCIETY THAILAND, 2022, 076, 1513-1874

Herein, highly dispersed 10-nm lithiophilic silver nanoparticles (AgNPs) were synthesized and decorated on 3D graphene aerogel supporting materials. The prelithiated AgNPs/3D graphene aerogel exhibits a high specific capacity of 1589 mAh/g at 0.1 A/g with a high initial coulombic efficiency (ICE) of ca. 93% and a long cycling stability over 500 cycles. A Li-ion battery cell using the prelithiated AgNPs/3D graphene aerogel with a finely tuned Ag content of 0.52 at. % as the anode and the Ni-rich LiNi0.88Co0.09Al0.03O2 as the cathode exhibits a high energy density of ∼290 Wh/kg at 0.1 C. This new anode material may be a useful high-energy anode for next-generation Li-ion batteries.

4. Mechanofusing Garnet Solid Electrolyte on the Surface of Ni-rich Layered Oxide Cathode towards High-Rate Capability of Cylindrical Li-ion Battery Cells
Panyawee Bunyanidhi, Nutthaphon Phattharasupakun, Chanikarn Tomon, Salatan Duangdangchote, Pinit Kidkhunthod, Montree Sawangphruk
Journal of Power Sources. 2022, 549, 232043
The interface between solid electrolytes and cathode materials determines charge storage mechanism of Li-ion batteries; however, it has not yet been fully investigated and understood. Herein, a diluted amount at 1 wt% of heterogenous lithium garnet Li7La3Zr2O12 (LLZO) solid electrolyte particles was chemically bonded to the Ni-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode by a scalable mechanofusion process. The interface chemistry was intensively investigated by an ex situ extended X-ray absorption fine structure (EXAFS). In situ X-ray diffraction was also used to investigate the charge storage mechanism of LLZO-NMC811. It was found that the LLZO-LaNiO3-NMC811 strong bond at the interface can enhance the microstructural stability leading to high-rate capability up to 7.5C. For the charge storage mechanism, the lithium intercalation/deintercalation in NMC-LLZO undergoes a slower phase transition since the LLZO-LaNiO3 interface can modulate Li concentration gradient and kinetics where the surface of NMC will not be fully emptied (during charge) or filled (during discharge). This will benefit the rate capability of LLZO-modified NMC material in which the Li concentration at the surface will not quickly reach a threshold value before the cut-off voltage. The practical applications of LLZO-NMC811 were eventually demonstrated in 2.1 Ah 18650-format cells with high-capacity retention and high-rate capability.

5.  Effect of charging protocols on electrochemical performance and failure mechanism of commercial level Ni-rich NMC811 thick electrode

Nutthaphon Phattharasupakun, Panyawee Bunyanidhi, Poramane Chiochan, Narong Chanlek, Montree Sawangphruk
Electrochemistry Communications, 2022, 139, 107309
Abstract: In order to bridge the gap between academia and industry in the development of cathode active material for high-energy lithium-ion batteries (LIBs), several experimental factors reflecting commercial use need to be considered. Herein, based on a thick commercial level NMC811 electrode, we simply demonstrated the effect of charging protocols on the rate performance, cycling stability, and Li storage mechanism. A constant current charge/discharge, typically used in most publications, was found to exhibit worse rate capability and cycling stability compared to the constant current constant voltage (CCCV) mode of charge, used in commercial LIB cells due to the less uniform Li concentration gradient between the surface and bulk of the material. In operando XRD also revealed that there was no negative impact from the rapid change in lattice parameters towards cycling performance. We also found that the major degradation mechanism of Ni-rich NMC811 showing poor cycling performance across literature, can be mainly ascribed to the thick cathode electrolyte interphase (CEI) resistive layer, hindering Li intercalation at high rate and also lead to lower accessible capacity in each cycle. This work illustrates a simple example of the gaps between research in academic and industry that need to be narrowed for the development of practical high energy materials.

6. Atomic Force Microscopy: An Advanced Imaging Technique—From Molecules to Morphologies
Jeevan Kumar Reddy Modigunta, Selvamani Vadivel, G. Murali, Insik In, Montree Sawangphruk
Microscopic Techniques for the Non-Expert, 2022
Abstract: Atomic force microscopy (AFM) is an extensively used advanced characterization technique for a nanoscale range of materials. This chapter clearly describes the importance and advantages of AFM, its working principles, modes of measurement, and its applications in interdisciplinary fields such as chemistry, materials science, and biology.

7.  Diffusion of Zirconium (IV) Ions from Coated Thick Zirconium Oxide Shell to the Bulk Structure of Ni-rich NMC811 Cathode Leading to High-performance 18650 Cylindrical Li-ion Batteries
Suchakree Tubtimkuna, Nutthaphon Phattharasupakun, Panyawee Bunyanidhi, Montree Sawangphruk
Advanced Materials Technology, 2022

Abstract: Herein, Ni-rich LiNi0.8Mn0.1Co0.1O2 or NMC811 cathode material, which is expected to be widely used soon, is coated by crystalline ZrO2 nanoparticles using green and scalable mechanofusion technique with an annealing process. A controllable synergistic effect of ZrO2 coating, as a spherical core–shell morphology with low surface energy, which is ideal for the process of electrode fabrication, and Zr4+ doping is carefully investigated. For the first time, the mechanofusion with the post-annealing at 800 °C used in this work can finely tune the shell thickness and doping gradient by the diffusion of Zr4+ from the coated ZrO2 shell to the bulk structure of NMC811. The optimized material, namely NMC@Zr-800 used as the cathode of 18650 cylindrical Li-ion batteries (LIBs), can provide excellent capacity retention over 1000 cycles at a severe 100% state-of-charge (SOC) at 1.0 C. Postmortem analysis shows that the material is stable with less crack formation and transition metal (TM) dissolution than the pristine NMC811 material owing to a synergistic effect of the surface protection by ZrO2 coating and Zr4+ doping. The results demonstrate the practical and scalable approach that will be beneficial for technological advancement in the high-energy 18650 cylindrical LIBs.

8.  Regulating the Cationic Rearrangement of Ni-rich Layered Oxide Cathode for High-performance Li-ion Batteries
Selvamani Vadivel, Krisara Srimanon, Montree Sawangphruk
Journal of Power Sources, 2022, 537, 231526

Abstract: Enormous effort has been paid to improve Ni-rich cathode's performance by suppressing surface residues and enhancing microscopic surface ordering (high Ni3+/Ni2+). Herein, strong alkali-mediated chemical oxidation of commercial precursor is employed to directly synthesize Ni-rich NCA cathode sintering under an oxygen atmosphere. Because of the limited lithium source, the lithium residue over the polycrystalline material is controlled; of course, a certain fraction of lithium has been lost and substituted by Ni2+, even pre-oxidized the precursor. XPS studies suggest that the percentage of oxidized nickel (Ni3+) is comparably higher at the surface than core (∼100 nm in depth) and retained during the lithiation. The synthesized material initially shows a high reversible lithiation efficiency of 90.6% at 0.05 C. The capacity degradation in the life-cycle study at 0.2 C could be endorsed to the combination of lithium inventory and active metal loss along with typical kinetic limitations, as diagnosed from the derivative dQ/dV plot. The high initial coulombic efficiency and discharge capacity with low polarization further confirm superior surface ordering and low surface residue. This study demonstrates that the pretreatment of the precursor is one of the effective strategies to regulate the cationic arrangement to achieve improved electrochemical performance.

9. Core-shell structure of LiMn2O4 cathode material reduces phase transition and Mn dissolution in Li-ion batteries
Chanikarn Tomon, Sangchai Sarawutanukul, Nutthaphon Phattharasupakun, Salatan Duangdangchote, Praeploy Chomkhuntod, Nattanon Joraleechanchai, Panyawee Bunyanidhi, Montree Sawangphruk
Communications Chemistry, 2022, 5 , 54
Abstract: Although the LiMn2O4 cathode can provide high nominal cell voltage, high thermal stability, low toxicity, and good safety in Li-ion batteries, it still suffers from capacity fading caused by the combination of structural transformation and transition metal dissolution. Herein, a carbon-coated LiMn2O4 cathode with core@shell structure (LMO@C) was therefore produced using a mechanofusion method. The LMO@C exhibits higher cycling stability as compared to the pristine LiMn2O4 (P-LMO) due to its high conductivity reducing impedance growth and phase transition. The carbon shell can reduce direct contact between the electrolyte and the cathode reducing side reactions and Mn dissolution. Thus, the cylindrical cell of LMO@C//graphite provides higher capacity retention after 900 cycles at 1 C. The amount of dissoluted Mn for the LMO@C is almost 2 times lower than that of the P-LMO after 200 cycles. Moreover, the LMO@C shows smaller change in lattice parameter or phase transition than P-LMO, indicating to the suppression of λ-MnO2 phase from the mixed phase of Li1-δMn2O4 + λ-MnO2 when Li-delithiation at highly charged state leading to an improved cycling reversibility. This work provides both fundamental understanding and manufacturing scale demonstration for practical 18650 Li-ion batteries.

10.  The charge density of intercalants inside layered birnessite manganese oxide nanosheets determining Zn-ion storage capability towards rechargeable Zn-ion batteries
Praeploy Chomkhuntod, Kanit Hantanasirisakul, Salatan Duangdangchote, Nutthaphon Phattharasupakuna, Montree Sawangphruk
Journal of Materials Chemistry A, 2022,  10,  5561-5568
Abstract: Rechargeable aqueous Zn–MnO2 batteries have been considered as one of the promising alternative energy technologies due to their high abundance, environmental friendliness, and safety of both Zn–metal anodes and manganese oxide cathodes. Although layer-type MnO2 (δ-MnO2) is one of the most promising intercalation cathode materials, there are some critical drawbacks such as sluggish Zn2+ diffusion kinetics and a phase transition of δ-MnO2 as a result of a strong electrostatic interaction between Zn2+ and the host structure. Herein, we systematically studied the effects of the charge density of pre-intercalated cations in layered MnO2 using Li+, Ca2+, and Al3+ on its structural properties and electrochemical performance as a cathode in aqueous Zn–MnO2 batteries. The results reveal that a small amount of highly charged intercalant can effectively stabilize the MnO2 layers, facilitating the kinetics of Zn2+ intercalation/deintercalation. As a result, Al–MnO2 exhibits superior capacity and a rate capability of 210 mA h g−1 with 21% capacity retention when the current density is increased from 0.1 to 2 A g−1, while Ca–MnO2 and Li–MnO2 exhibit 189 and 160 mA h g−1 with a capacity retention of 17% and 11%, respectively. The superior capacity of Al–MnO2 is attributed to the enhanced redox activity from more Mn electrochemical utilization as confirmed by ex situ X-ray photoelectron spectroscopy. Moreover, the long-term cycling stability evaluated at 2 A g−1 shows that Al–MnO2 exhibits superior cycling stability with 84% capacity retention over 2000 cycles. As revealed by ex situ X-ray diffraction and theoretical calculations, the highly charged intercalant can minimize the binding energy between Zn2+ and the MnO2 host, alleviating the strong electrostatic attraction that can induce reversible Zn2+ insertion/extraction.

11.  Enzyme-immobilized 3D silver nanoparticle/graphene aerogel composites towards biosensors

Wongduan Sroysee, Ketsuda Kongsawatvoragul, Phitchayapha Phattharaphuti, Pattranit Kullawattanapokin, Chonticha Jangsan, Worapol Tejangkura, Montree Sawangphruk
Materials Chemistry and Physics,  2022,  277,  125572

The detection of allergen sulfite is essential for food quality control and public health supervision. Here, a high-performance sulfite biosensor was developed from a sulfite oxidase enzyme (SOx) immobilized on silver nanoparticles (AgNPs) decorated on 3D reduced graphene oxide (3D-rGO). 3D-rGO with high specific pore volume and high electroactive surface area is ideal as a supporting material. AgNPs further provide high electrical conductivity or fast charge transfer and serve as an enzyme anchoring site via a stable thiol bonding. The composite material was initially functionalized with the folic acid and cysteine namely rGO@Ag-Cys-FA before immobilized with the SOx. The resultant rGO@Ag-Cys-FA-SOx exhibits high sensitivity and selectivity towards sulfite detection, high bio-electrocatalytic activity, and fast heterogeneous electron transfer rate constant. The biosensor is also tested in a continuous flow injection system to demonstrate the practical use. Besides, the as-produced sensor in this work can be used in the real sample, which is the canned fruit product indicating its potential practical application.

12.  Free carbonate-based molecules in the electrolyte leading to severe safety concern of Ni-rich Li-ion batteries

Nattanon Joraleechanchai, Ruttiyakorn Donthongkwa, Salatan Duangdangchote, Nutthaphon Phattharasupakun, Poramane Chiochan, Kan Homlamai and Montree Sawangphruk  
Chemical Communications,  2022,  58,  779-782

Abstract: The safety of Li-ion batteries is one of the most important factors, if not the most, determining their practical applications. We have found that free carbonate-based solvent molecules in the hybrid electrolyte system can cause a severe safety concern. Mixing ionic liquids to the carbonate-based solvent as the co-solvent at fixed 1M LiPF6 salt can lead to free carbonate-based molecules causing poor charge storage performance and safety concerns.


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