Article
Chemistry, Physical
Nebi Yelegen, Berre Kumuk, Ruveyda N. Kaplan, Mustafa Ilbas, Yuksel Kaplan
Summary: This study conducted performance tests on a unitized regenerative PEM electrolyzer/fuel cell and performed numerical modeling. The validity of the developed model was confirmed by experimental results. Prior to the performance tests, leakproofness tests were conducted and the appropriate torque force was optimized to reduce contact resistance and performance loss. In the electrolyzer mode, 0.019 slpm of hydrogen and 0.0095 slpm of oxygen gas were produced, while a power density of 0.353 W/cm2 was obtained in the fuel cell mode.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Review
Environmental Studies
Teresa Maria Gulotta, Roberta Salomone, Francesco Lanuzza, Giuseppe Saija, Giovanni Mondello, Giuseppe Ioppolo
Summary: Unitized Regenerative Fuel Cell (URFC) is a promising green hydrogen technology for clean energy production, but further research is needed to make it more attractive across various sectors. The analysis of Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) studies on URFCs using proton exchange membrane (PEM) devices reveals varying environmental and economic impacts, highlighting the need for increased transparency and harmonization in these assessments.
ENVIRONMENTAL IMPACT ASSESSMENT REVIEW
(2022)
Article
Chemistry, Physical
Jie Yang, Ruimin Ding, Chang Liu, Shanshan Liu, Qinchao Xu, Lifang Chen, Jingchao Chen, Junfen Li, Xi Yin
Summary: A highly efficient unitized regenerative hydrogen peroxide cycle cell (UR-HPCC) has been developed for renewable energy storage. This cell utilizes a carbon-based platinum group metal-free catalyst as the bifunctional oxygen electrode catalyst, showing high efficiency in oxidation and reduction reactions. Thermodynamic analysis reveals that the UR-HPCC exhibits superior energy efficiency and reversibility compared to conventional unitized regenerative fuel cells.
JOURNAL OF POWER SOURCES
(2022)
Article
Chemistry, Physical
Ahyoun Lim, Ju Sung Lee, Suji Lee, So Young Lee, Hyoung-juhn Kim, Sung Jong Yoo, Jong Hyun Jang, Yung-Eun Sung, Hyun S. Park
Summary: In this study, the water flux of the anode and cathode electrodes is systematically controlled by manipulating the relative humidity of the supplied gas and altering the selection of the electrode in amphiphilic membrane electrode assembly. By investigating the operation factors of URFC, a high round trip efficiency of 51 % (@ 0.4 A cm(-2)) was achieved with only 0.65 mg((Pt+Ir)) cm(-2) of the noble catalyst.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Review
Chemistry, Physical
Shiyi Wang, Adam Z. Weber, Xiong Peng
Summary: This review highlights recent progress on high-performing PEM-URFCs, focusing on electrode engineering, key components, and operating approaches that consider realistic conditions. The study also discusses key components of a membrane electrode assembly (MEA), including the catalyst layer, diffusion media, and membrane, which require different optimization strategies.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Green & Sustainable Science & Technology
A. Rochaa, R. B. Ferreira, D. S. Falcaoa, A. M. F. R. Pinto
Summary: This study compares the performance of different bipolar plates and gas diffusion layers in a unitized regenerative fuel cell. The results show that carbon materials perform better in the cathode, while titanium materials are still required in the anode. Additionally, optimizing the operating conditions of the URFC can improve its efficiency.
Article
Chemistry, Physical
Siddharth Komini Babu, Abdurrahman Yilmaz, Md Aman Uddin, Jacob LaManna, Eli Baltic, David L. Jacobson, Ugur Pasaogullari, Jacob S. Spendelow
Summary: This research introduces a new porous transport layer (PTL), called hydrochannel PTL, that improves water management and achieves record high round trip efficiency in unitized reversible fuel cells (URFCs). URFCs require fast transport of O2 and H2O for high performance in both fuel cell and water electrolyzer modes, but the conflicting water management requirements make cell design complicated. The hydrochannel PTL addresses this issue by providing hydrophilic channels for water transport through a hydrophobic PTL, optimizing performance in both modes. Neutron radiography measurements confirm that the hydrochannel PTL enhances performance due to its improved water management capabilities.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
L. Padilla Urbina, J. Liu, N. Semagina, M. Secanell
Summary: Inkjet printing is a feasible technique for the fabrication of electrode in unitized regenerative fuel cells (URFCs) and the study of optimal ionomer and catalyst loading. A physical mixture of Pt, IrOx, and Nafion ionomer was directly inkjet printed on a Nafion membrane to create bifunctional oxygen electrodes with varying loading for a URFC. The results show that the optimal electrode requires low ionomer loading and significantly less IrOx catalyst than platinum.
JOURNAL OF POWER SOURCES
(2023)
Article
Thermodynamics
Ping'an Li, Diankai Qiu, Linfa Peng, Shuiyun Shen, Xinmin Lai
Summary: In this study, an experimental measurement protocol for the degradation of Unitized Regenerative Fuel Cell (URFC) was established, confirming that the degradation mainly occurs in the water electrolysis mode. Carbon corrosion on the MPL side of the GDL was found to be the main cause of URFC degradation, leading to a reduction in water transport capacity and an increase in CCM proton conduction resistance.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Chemistry, Physical
Noor ul Hassan, Prabhu Ganesan, Aaron A. Lando, William E. Mustain, Hector R. Colon-Mercado
Summary: Anion exchange membrane unitized regenerative fuel cells (AEM-URFCs) are a promising technology for energy storage and electricity production, but their efficiency is limited by the kinetics of the bifunctional oxygen electrode. This study advances the efficiency of the oxygen electrode by using new electrocatalysts, achieving high round trip efficiency and the highest performance reported to date in AEM-URFCs.
JOURNAL OF POWER SOURCES
(2022)
Article
Chemistry, Physical
Cheoulwoo Oh, Man Ho Han, Young-Jin Ko, Jun Sik Cho, Min Wook Pin, Peter Strasser, Jae-Young Choi, Hansung Kim, Chang Hyuck Choi, Woong Hee Lee, Hyung-Suk Oh
Summary: This study synthesized a Pt-Ni alloy catalyst to improve the durability of anion exchange membrane-based unitized regenerative fuel cells (AEM-URFCs) and revealed the underlying mechanism.
ADVANCED ENERGY MATERIALS
(2023)
Article
Green & Sustainable Science & Technology
Hang Guo, Jia Song, Fang Ye, M. A. Chong Fang
Summary: The oxygen side flow channel structures have a significant influence on the dynamic response of relevant parameters during the operation mode switching procedures of a unitized regenerative fuel cell. The study compared the influence of eight oxygen-side channels on the mode switching process and found that the required time for parameters to reach a stable state in the fuel cell mode is longer when using orientational flow channels. Additionally, different flow channel structures affect the time required to stabilize each parameter during mode switching, but do not change the characteristics of the stable state mode.
Article
Chemistry, Physical
Xiejing Luo, Luqi Chang, Chenhao Ren, Jiuhong Zhang, Dawei Zhang, Jizheng Yao, Jie Song, Zhanfeng Deng, Chaofang Dong, Xiaogang Li
Summary: This study proposes a sandwich-like C/(Ti:C)/Ti modified Ti bipolar plates, and through computational simulations and experimental verification, it demonstrates that the bipolar plates have lower interfacial contact resistance and smaller corrosion current density, making them suitable for various operating conditions.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
Shaolan Mo, Chun Jin, Feng Wang, Chen Wen, Nan Wang, Lei Feng, Jingying Bai, Jingjun Liu
Summary: The study developed bifunctional oxygen catalysts with double active sites, showing higher activity and stability compared to commercial catalysts. The strong particle-to-particle interaction between PtCoW and neighboring Ir, along with the formed IrO2 parallel to Ir epitaxial structure, were the main reasons for the enhanced performance.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
A. Costa, F. Viana, F. Toptan, J. Geringer
Summary: Highly porous Ti was found to exhibit significant load- and amplitude-dependent responses under fretting-corrosion conditions, with different slip regimes and OCP variations. The promising structure of this Ti was preserved even after 16 hours of fretting-corrosion under severe solicitations.
Article
Chemistry, Physical
Hee Soo Kim, Jihyun Choi, Jimin Kong, Hansung Kim, Sung Jong Yoo, Hyun S. Park
Summary: The electrochemical nitrogen reduction reaction (NRR) is a promising method for energy-efficient and low-emission NH3 production. A copper sulfide-based electrocatalyst is used for electrochemical NH3 production, but the catalyst undergoes reductive degradation during the NRR process. A regenerative electrochemical sulfur cycle is introduced to revive the crystal structure and NRR activities of Cu9S5 for continuous electrochemical NH3 production.
Article
Chemistry, Multidisciplinary
Mingyu Lee, Semin Kim, Minsoo Jang, Hyun S. Park, Jae Young Lee
Summary: In this study, a novel strategy was proposed to fabricate a high-performance biosensor platform by one-step electrochemical coating of PDA/PPy with enzymes (GOx and LOx). The PDA/PPy/GOx biosensor exhibited significantly improved sensitivity and stability compared to PPy/GOx, while the PDA/PPy/LOx biosensor showed enhanced lactate sensing ability. This facile fabrication strategy involving PDA/PPy and enzymes serves as an attractive platform for highly sensitive and stable biosensors.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Kyungjung Kwon, Kang Hee Lee, Dong Ho Um, Seon-ah Jin, Hyun S. Park, Jinwon Cho, Jinho Hyun, Hyung Chul Ham, Chanho Pak
Summary: PdIr nanoparticles supported on carbon exhibit enhanced ORR activity and durability compared to Pd monometallic catalysts in polymer electrolyte membrane fuel cells. Their improved stability is attributed to the synergistic effect of Pd and Ir, as well as the formation of phase-separated nanoalloys with a Pd-rich surface.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2021)
Article
Engineering, Chemical
Ji Eun Park, Junghwan Kim, Jusung Han, Kihyun Kim, SungBin Park, Sungjun Kim, Hyun S. Park, Yong-Hun Cho, Jong-Chan Lee, Yung-Eun Sung
Summary: The sulfonated poly(arylene ether sulfone) with a 50 mol.% degree of sulfonation, SPAES50, has been successfully synthesized for use in hydrocarbon-based membrane and ionomer applications in proton-exchange membrane water electrolysis (PEMWE). The SPAES50 membrane and the SPAES50-based ionomer (P50) were found to exhibit excellent physical and electrochemical properties, leading to higher performance in PEMWE compared to the commercial Nafion (TM) membrane and ionomer. This study demonstrates the great potential of SPAES50 as a hydrocarbon-based membrane and ionomer for PEMWE applications.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Polymer Science
Ji Eon Chae, So Young Lee, Sung Jong Yoo, Jin Young Kim, Jong Hyun Jang, Hee-Young Park, Hyun Seo Park, Bora Seo, Dirk Henkensmeier, Kwang Ho Song, Hyoung-Juhn Kim
Summary: By modifying and treating polystyrene, a series of ionomers for AEMFCs were prepared, with performance affected by various factors, achieving a maximal power density of 407 mW cm(-2).
Article
Nanoscience & Nanotechnology
Hui-Yun Jeong, Dong-Gun Kim, Shedrack G. Akpe, Vinod K. Paidi, Hyun S. Park, Soo-Hyoung Lee, Kug-Seung Lee, Hyung Chul Ham, Pil Kim, Sung Jong Yoo
Summary: A simple wet-chemical route was developed to prepare core-shell-structured catalysts with high oxygen reduction reaction (ORR) activity using a low Pt loading amount. The thin Pt layer on Ni3N nanoparticles exhibited 5 times higher mass activity and specific activity than that of commercial Pt/C. This method can be utilized to prepare various transition-metal-based core-shell nanocatalysts for energy conversion reactions.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Nanoscience & Nanotechnology
Jimin Kong, Min-Seok Kim, Ramavi Akbar, Hee Young Park, Jong Hyun Jang, Hansung Kim, Kahyun Hur, Hyun S. Park
Summary: The Fe-CuS/C catalyst exhibits a high NH3 production rate in the nitrogen reduction reaction, but rapid degradation of the catalyst hinders precise investigation in longer measurements. However, when the degradation effect is mitigated, the NH3 production rate is enhanced with increased overpotentials.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
In Gyeom Kim, Ahyoun Lim, Jong Hyun Jang, Kwan-Young Lee, In Wook Nah, Sehkyu Park
Summary: This study demonstrates the unprecedentedly high oxygen evolution reaction (OER) performance of binary iridium (Ir) and ruthenium (Ru) nanoparticles on TiO2-oxide-decorated reduced graphene oxide (rGO) in acidic media. The IrRu alloy electrocatalysts supported on TiO2-rGO show optimal OER performances and high stability, with the IrRu/T90G10 sample exhibiting remarkable OER activity and enhanced stability compared to unsupported catalysts.
JOURNAL OF POWER SOURCES
(2021)
Article
Chemistry, Multidisciplinary
Haneul Jin, Songa Choi, Gi Joo Bang, Taehyun Kwon, Hee Soo Kim, Su Ji Lee, Yongju Hong, Dong Wook Lee, Hyun S. Park, Hionsuck Baik, Yousung Jung, Sung Jong Yoo, Kwangyeol Lee
Summary: The study found that by controlling the mixture of Pt atoms with the RuO2 matrix in acidic water electrooxidation, the durability and activity of RuO2 can be improved, resulting in the preparation of highly efficient PtCo-RuO2/C nanorods. These nanorods show lower overpotential and strong mass activity in half-cell tests, while also exhibiting long-term stability. Additionally, Pt dopants promote the adsorption and deprotonation processes in the oxygen evolution reaction, thereby limiting Ru overoxidation.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
Article
Engineering, Chemical
Malikah Najibah, Ekaterina Tsoy, Hamza Khalid, Yongfang Chen, Qingfeng Li, Chulsung Bae, Jaromir Hnat, Michaela Plevov, Karel Bouzek, Jong Hyun Jang, Hyun S. Park, Dirk Henkensmeier
Summary: The study investigates the reinforcement of anion exchange membranes using polybenzimidazole nanofiber mats filled with the bromomethylated precursor of ultra-stable AEM material mTPN. The optimized PBI/mTPN-50.120 composite membrane shows decreased length swelling, increased tensile strength, and Young's modulus while maintaining high conductivity. In an electrolyser, the membrane demonstrated stable performance over 200 hours of testing.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Article
Chemistry, Physical
Hee Soo Kim, Haneul Jin, Seung-Hoon Kim, Jihyun Choi, Dong Wook Lee, Hyung Chul Ham, Sung Jong Yoo, Hyun S. Park
Summary: The introduction of a sacrificial dopant enhances the activity and durability of eNRR catalysts, leading to more efficient ammonia production.
Article
Chemistry, Multidisciplinary
Sinwoo Kang, Changbin Im, Ioannis Spanos, Kahyun Ham, Ahyoun Lim, Timo Jacob, Robert Schloegl, Jaeyoung Lee
Summary: In this study, the degradation of NiFe-based oxides in Fe-purified KOH was investigated, and a solution was proposed. Loading TPP on the catalyst/electrolyte interface can alleviate the destabilization of NiFe (oxy)hydroxide and prolong the catalyst's lifetime.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Engineering, Electrical & Electronic
Barosaim Sung, Hyun-Gi Seok, Jaekwon Kim, Jaehoon Lee, Taejin Jang, Ilhoon Jang, Youngmin Kim, Anna Yu, Jong-Hyun Jang, Jiyoung Lee, Jeongyeol Bae, Euiyoung Park, Sungjun Lee, Seokwon Lee, Joohan Kim, Beomkon Kim, Yong Lim, Seunghyun Oh, Jongwoo Lee
Summary: The world's first 5-carrier aggregation using digital-intermediate frequency receiver is presented, which supports 5G sub-6 GHz new radio and maintains 2G and 3G. The integration of three digital-IF RXs with a shared local oscillator-phase-locked loop reduces power consumption and area. The estimated power saving by sharing a single LO-PLL is 17%.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2022)
Article
Chemistry, Multidisciplinary
Muhammad Luthfi Akbar Trisno, Asridin Dayan, Su Ji Lee, Franz Egert, Martina Gerle, Mikkel Rykaer Kraglund, Jens Oluf Jensen, David Aili, Aleksandra Roznowska, Artur Michalak, Hyun S. Park, Fatemeh Razmjooei, Syed-Asif Ansar, Dirk Henkensmeier
Summary: This study presents a new membrane fabrication process using PBI and KOH to create high conductivity membranes. The PBI cast membranes showed a significantly higher conductivity than conventional PBI membranes. The addition of a porous support also improved the mechanical strength and stability of the KOH doped PBI membranes.
ENERGY & ENVIRONMENTAL SCIENCE
(2022)
