Sex: Female

  • Doctor of Philosophy in Materials Science and Engineering, Hokkaido University, 2018
  • Master of Science in Materials Science and Engineering, University of the Philippines, 2014
  • Bachelor of Science in Chemical Engineering, University of Santo Tomas, 2009

Field of Specialization
Material characterization
X-ray Diffraction
Material Characteristics
Thin Films and Nanotechnology
Materials Processing
Mechanical Properties


Article title: Manganese Dioxide (MnO2): A High-Performance Energy Material for Electrochemical Energy Storage Applications
Authors: Ryan D. Corpuz, Lyn Marie De Juan-Corpuz & Soorathep Kheawhom
Publication title: Metal and Metal Oxides for Energy and Electronics 91-119, 2020

This chapter highlights the development of manganese oxide (MnO2) as cathode material in rechargeable zinc ion batteries (ZIBs). Recently, renewed interest in ZIBs has been witnessed due to the demand for economical, safe, and high-performance rechargeable batteries which is the current limitation of the widely used rechargeable lithium ion batteries (LIBs). ZIBs in comparison with LIBs have a high volumetric capacity and an abundance of raw material. ZIBs are also non-toxic and safe. Besides, production of ZIBs does not require sophisticated equipment such as vacuum technology. In fact, ZIBs can be manufactured even under ambient atmosphere. Of the interesting cathode materials for ZIBs such as V2O5 and Prussian Blue analogs, MnO2 attracts much research attention due to its rich electrochemistry, size, morphology, phase, and structure. Similar to Zn, MnO2 is plentiful and safe. It is evident that when paired up with zinc, MnO2 can deliver a high theoretical capacity of 308 mAh g−1. However, the inherent poor conductivity and poor cyclability of this material are common drawbacks for its potential usage.
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Article title: S., Binder-Free α-MnO2 Nanowires on Carbon Cloth as Cathode Material for Zinc-Ion Batteries
Authors: Ryan Dula Corpuz, Lyn Marie De Juan-Corpuz, Mai Thanh Nguyen, Tetsu Yonezawa, Heng-Liang Wu, Anongnat Somwangthanaroj, and Soorathep Kheawhom
Publication title: International Journal of Molecular Sciences 21(9):3113, 2020

Recently, rechargeable zinc-ion batteries (ZIBs) have gained a considerable amount of attention due to their high safety, low toxicity, abundance, and low cost. Traditionally, a composite manganese oxide (MnO2) and a conductive carbon having a polymeric binder are used as a positive electrode. In general, a binder is employed to bond all materials together and to prevent detachment and dissolution of the active materials. Herein, the synthesis of α-MnO2 nanowires on carbon cloth via a simple one-step hydrothermal process and its electrochemical performance, as a binder-free cathode in aqueous and nonaqueous-based ZIBs, is duly reported. Morphological and elemental analyses reveal a single crystal α-MnO2 having homogeneous nanowire morphology with preferential growth along {001}. It is significant that analysis of the electrochemical performance of the α-MnO2 nanowires demonstrates more stable capacity and superior cyclability in a dimethyl sulfoxide (DMSO) electrolyte ZIB than in an aqueous electrolyte system. This is because DMSO can prevent irreversible proton insertion as well as unfavorable dendritic zinc deposition. The application of the binder-free α-MnO2 nanowires cathode in DMSO can promote follow-up research on the high cyclability of ZIBs.
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Article title: Binder-Free Centimeter-Long V2O5 Nanofibers on Carbon Cloth as Cathode Material for Zinc-Ion Batteries
Authors: Lyn Marie De Juan-Corpuz, Ryan Dula Corpuz, Anongnat Somwangthanaroj, Mai Thanh Nguyen, Tetsu Yonezawa , Jianmin Ma, and Soorathep Kheawhom
Publication title: Energies 13(1), December 2019

Recently, rechargeable aqueous zinc-ion batteries (AZBs) have attracted extensive interest due to their safety, abundance, low cost, and low toxicity. However, aqueous electrolytes require a polymeric binder to prevent dissolution of the active material in addition to its binding properties. This study highlights binder-free, centimeter long, single-crystal, V 2 O 5 nanofibers (BCS-VONF) on carbon cloth, as the cathode material for AZBs synthesized via a simple one-step hydrothermal process. BCS-VONF in 3.0 M Zn(OTf) 2 exhibit promising electrochemical performance with excellent capacity retention. Even in the absence of a binder, BCS-VONF were found to be very stable in 3.0 M Zn(OTf) 2. They will not yield to the dissolution and detachment of the active material on the current collector. The novel strategy described in this study is an essential step for the development of BCS-VONF on carbon cloth, as a promising cathode material for AZBs.
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Article title: Annealing induced a well-ordered single crystal δ-MnO2 and its electrochemical performance in zinc-ion battery
Authors: Ryan Dula Corpuz, Lyn Marie Z. De Juan, Supareak Praserthdam, Rojana Pornprasertsuk, Tetsu Yonezawa, Mai Thanh Nguyen, Soorathep Kheawhom
Publication title: Scientific reports 9(1):15107, October 2019

Herein, the formation and electrochemical performance of a novel binder-free turbostratic stacked/ well-ordered stacked δ-MnO2-carbon fiber composite cathodes in deep eutectic solvent (DES) based zinc-ion battery (ZIB) is reported. Results of morphological, elemental, and structural analyses revealed directly grown and interconnected δ-MnO2 crumpled nanosheets on a carbon fiber substrate. Moreover, an improvement via a simple annealing strategy in the stacking, surface area and conductivity of the δ-MnO2 sheets was observed. Annealing induces the rearrangement of δ-MnO2 sheets resulting in the transformation from turbostratic stacking to a well-ordered stacking of [Formula: see text]-MnO2 sheets, as indicated by the selected area electron diffraction (SAED) hexagonal single crystal pattern. Besides, the formation of the well-ordered stacking of [Formula: see text]-MnO2 sheets exhibited improved electrochemical performance and cyclability, as cathode material for ZIB. The novel strategy described in this study is an essential step for the development of binder-free δ-MnO2-C fiber composite with a well-ordered stacking of δ-MnO2 sheets. This study also demonstrated comparable electrochemical performance between the turbostratic [Formula: see text]-MnO2 sheets and the well-ordered stacked δ-MnO2 sheets.
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Article title: Porous ZnV2O4 Nanowire for Stable and High-Rate Lithium-Ion Battery Anodes,
Authors: Lyn Marie Z. De Juan-Corpuz, Mai Thanh Nguyen, Ryan D. Corpuz, Tetsu Yonezawa, Nataly Carolina Rosero-Navarro, Kiyoharu Tadanaga, Tomoharu Tokunaga, and Soorathep Kheawhom
Publication title: Applied Nanomaterials 2(7): 4247-4256, June 2019

Porous ZnV2O4 nanowires (NWs) were successfully prepared by hydrothermal reaction followed by calcination. Despite the porous structure, these porous ZnV2O4 NWs are single crystal with {220} facets and a wire direction along the c-axis. On the basis of an electrochemical test, these porous ZnV2O4 NWs have better cycling stability and higher specific capacity (i.e., 460 mA h g–1 after 100 cycles and 149 mA h g–1 after 1000 cycles using 1 and 5 A g–1 current densities, respectively) compared to other morphologies (i.e., spherical and coral-like morphologies). As a ternary transition metal oxide, the produced porous ZnV2O4 NWs undergo phase transformation without compromising the resulting capacity. On the other hand, the CV curves at different scan rates indicate a pseudocapacitive electrochemical behavior of the porous ZnV2O4.
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Article title: Electrochemical exploration of the effects of calcination temperature of a mesoporous zinc vanadate anode material on the performance of Na-ion batteries
Authors: Rasu Muruganantham, Irish Valerie Buiser Maggay, Lyn Marie Z. De Juan, Mai Thanh Nguyen, Tetsu Yonezawa, Chia-Her Lin, Yan-Gu Lind and Wei-Ren Liu
Publication title: Inorganic Chemistry Frontiers, June 2019

Nowadays, transition metal oxide is rapidly developed for Na-ion storage anode materials, which provides relatively high theoretical capacity than the graphitic anode. However, the evaluations of enhanced electrochemical performance of NIBs are ongoing progress via various approaches such as coating or doping and so on. Hence this work, Spinel structure bimetal oxide ZnV2O4 mesoporous material is successfully synthesized via solvothermal technique followed by calcined at different temperatures. The impacts of calcination temperatures on the Na-ion storage anode performance are thoroughly investigated for the first time. The initial discharge capacities of 178, 251, 296 mAh∙g-1 are obtained for 500, 600, and 700°C, respectively. After 250 cycles, ZVO-700 electrode exhibits to retain 166 mAh.g-1 at 200 mA∙g-1 with a high coulombic efficiency of 99%. Meanwhile, ZVO-500 and ZVO-600 retained 55 mAh∙g-1 and 99 mAh∙g-1 with ~27% and ~42% retention rate, respectively. The electrochemical Na-ion storage is predicted by the conversion reaction of ZnV2O4. Moreover, the ZVO-700 sample showed a higher surface area and pore volume than that of ZVO-500 and ZVO-600 °C samples, which leads to remarkable electrochemical performance.
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Article title: Electrochemical properties of novel FeV2O4 as an anode for Na-ion batteries
Authors: Irish Valerie B. Maggay, Lyn Marie Z. De Juan, Jeng-Shin Lu, Mai Thanh Nguyen, Tetsu Yonezawa, Ting-Shan Chan & Wei-Ren Liu
Publication title: Scientific Reports 8(1), June 2018

Spinel based transition metal oxide - FeV2O4 is applied as a novel anode for sodium-ion battery. The electrochemical tests indicate that FeV2O4 is generally controlled by pseudo-capacitive process. Using cost-effective and eco-friendly aqueous based binders, Sodium-Carboxymethylcellulose/Styrene butadiene rubber, a highly stable capacity of ~97 mAh∙g-1 is obtained after 200 cycles. This is attributed to the strong hydrogen bonding of carboxyl and hydroxyl groups indicating superior binding with the active material and current collector which is confirmed by the ex-situ cross-section images of the electrode. Meanwhile, only ~27 mAh∙g-1 is provided by the electrode using poly(vinylidene difluoride) due to severe detachment of the electrode material from the Cu foil after 200 cycles. The obtained results provide an insight into the possible applications of FeV2O4 as an anode material and the use of water-based binders to obtain highly stable electrochemical tests for sodium-ion battery.
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Article title: β-Sn nanorods with Active (001) Tip Induced LiF-Rich SEI Layer for Stable Anode Material in Lithium-ion Battery
Authors: Lyn Marie Z. De Juan, Irish Valerie B. Maggay, Mai Thanh Nguyen, Wei-Ren Liu, and Tetsu Yonezawa
Publication title: Applied Nanomaterials 1(7): 3509-3519, 2018

β-Sn nanorod (NR) with (200) facets and (001) tip is a potential anode material in lithium ion battery (LIB) due to its good cycle stability that can retain ∼600 and 550 mA h g–1 after 100 cycles using 0.2 C for high and low aspect ratios, respectively. The high stability compared to that of spherical nanoparticles can be attributed to the combination of the nanorod morphology that buffers large volumetric change, and the LiF-rich F-containing surface electrolyte interface (SEI) layer that allows for a stable SEI layer and a good ionic and electronic conductivity. The lower SEI resistivity and high Li+ diffusivity of low aspect ratio β-Sn NRs resulted in a better cyclability compared to high aspect ratio β-Sn NRs. These can be attributed to the higher specific surface area of highly reactive (001) surface, i.e., the tip of the rod, that produces a LiF-rich F-containing SEI layer of the lower aspect ratio compared to that of the higher aspect ratio β-Sn NRs.
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Article title: ZnV 2 O 4 : A potential anode material for sodium-ion batteries
Authors: Irish Valerie Buiser Maggay, Lyn Marie Z. De Juan, Mai Thanh Nguyen, Tetsu Yonezawa, B .K. Chang, T. S. Chan, Wei-Ren Liu
Publication title: Journal of the Taiwan Institute of Chemical Engineers 88 :161-168, July 2018

A template-free solvothermal method was employed to successfully obtain ZnV2O4 spinel oxide and its electrochemical properties as anode materials for sodium ion battery system were investigated for the first time. The structural, morphological, elemental composition, electrochemical properties and theoretical calculations of the as-prepared ZnV2O4 were carried out. XRD revealed the presence of ZnO and VO2 impurities when synthesized for 1 day, while complete formation of ZnV2O4 was attained when the synthesis procedure was increased to 3 days. When cycled at 50 mA/g, it delivered an initial capacity of as high as 537 mAh/g at a potential window of 0.01–3.0 V. Meanwhile, a reversible capacity of ∼ 113 mAh/g was obtained when cycled at 100 mA/g for 30 cycles. These results indicate the potential applications of ZnV2O4 as anode materials for sodium ion battery systems.
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Article title: Structural Control Parameters for Formation of Single-Crystalline β-Sn Nanorods in Organic Phase
Authors: Lyn Marie Z. De Juan, Mai Thanh Nguyen, Tetsu Yonezawa*Orcid, Tomoharu Tokunaga, Hiroki Tsukamoto, and Yohei Ishida
Publication title: Crystal Growth & Design 17(9), July 2017

For the first time, investigation on the effect of lowering the synthesis temperature below room temperature (10 to -10 °C) and increasing the viscosity of the reaction solution at certain temperatures have been used to trigger the formation of single-crystalline β-Sn nanorods (NRs) in a chemical synthesis using an organic solvent. These two parameters govern the energy of the particles in the solution, thereby mediating the selective attachment to the nuclei and the preferential growth of Sn along the c-axis. The length and aspect ratio of the NRs were inversely proportional to the synthesis temperature and directly proportional to the viscosity of the reaction solution. In addition, we found that poly(vinylpyrrolidone) (PVP) with a high molecular weight aided the formation of longer and higher aspect ratio NRs via the bridge flocculation effect.
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