Article
Electrochemistry
Hong Ren, Xiangchao Meng, Yongli Lin, Zhigang Shao
Summary: In this study, a two-pronged catalyst layer preparation method is proposed to independently regulate the deposited ionomer formed by free ionomers in the catalyst ink. The characteristics of free ionomer in the catalyst ink were found to affect the ionomer distribution and pore structure in the catalyst layer, thus influencing proton conduction and mass transport. Compared with the conventional method, the electrode prepared by the two-pronged method exhibited improved performance, with a decrease in proton conduction resistance by 54.7%, a reduction in ionomer film thickness on catalyst particles surface by about 2 nm, and an increase in power density of the single cell by 40.4% at a current density of 2500 mA cm-2.
ELECTROCHIMICA ACTA
(2023)
Article
Chemistry, Physical
Hong Ren, Yue Teng, Xiangchao Meng, Dahui Fang, He Huang, Jiangtao Geng, Zhigang Shao
Summary: This study investigates the performance and internal mechanism of SSC PFSA ionomers in proton exchange membrane fuel cells, revealing the correlation between the distribution of different EW ionomers in CL and their performance. By increasing IEC and reducing ionomer adsorption on Pt/C, the formation of Pt/C-ionomer connection network is facilitated, leading to a more uniform ionomer proton conduction network in the CL.
JOURNAL OF POWER SOURCES
(2021)
Article
Chemistry, Physical
Lei Liu, Chao Wang, Zhenfeng He, Duo Pan, Binbin Dong, Sravanthi Vupputuri, Zhanhu Guo
Summary: Nafion/APNB membranes were prepared by introducing APNB architecture, increasing hydrophobic domains, and forming ordered water channels to improve ion conductivity; Nafion/APNB-2.5% membrane has the highest swelling ratio, while Nafion/APNB-5% membrane has the highest power density.
JOURNAL OF POWER SOURCES
(2021)
Review
Chemistry, Physical
Xiaohui Yan, Zhiling Xu, Shu Yuan, Aidi Han, Yuanting Shen, Xiaojing Cheng, Yuwei Liang, Shuiyun Shen, Junliang Zhang
Summary: This review summarizes the importance of PFSA ionomer in proton exchange membrane fuel cells (PEMFCs) and its influence on fuel cell performance. By comparing the properties of PFSA bulk membrane and ultrathin ionomer film, as well as the microstructure and proton conduction behavior of the ionomer in the catalyst layer, the impact mechanism of the ionomer on fuel cell performance is revealed. Modifying the chemical structure of the ionomer and engineering the interaction between the ionomer and catalyst hold promise for greatly improving the performance of ultra-low platinum loading PEMFCs.
JOURNAL OF POWER SOURCES
(2022)
Article
Nanoscience & Nanotechnology
Masashi Harada, Hiroaki Kadoura, Shin-ichi Takata, Hiroki Iwase, Shuji Kajiya, Takahisa Suzuki, Naoki Hasegawa, Akihiro Shinohara, Satoru Kato
Summary: The performance of a polymer electrolyte fuel cell can be enhanced by improving the proton conductivity of the catalyst layer, which is influenced by both ionomer content and carbon support. A novel proton conductivity model is introduced to simulate catalyst layers with different amounts of ionomers and carbon types. The model considers the presence of thin-film ionomers with suppressed proton conductivities and suggests that reducing the fraction of thin-film ionomers or avoiding factors that suppress their proton conduction improves the performance of the catalyst layer.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Environmental Sciences
Asif Jamil, Sikander Rafiq, Tanveer Iqbal, Hafiza Aroosa Aslam Khan, Haris Mahmood Khan, Babar Azeem, M. Z. Mustafa, Abdulkader S. Hanbazazah
Summary: Fuel cells are environmentally friendly technology with high efficiency and economic advantages. Proton exchange membranes, especially for hydrogen fuel cells, have great potential but face challenges in terms of cost and degradation of proton exchange capacity over time.
Article
Green & Sustainable Science & Technology
Xiang Li, Fumin Tang, Qianqian Wang, Bing Li, Haifeng Dai, Guofeng Chang, Cunman Zhang, Pingwen Ming
Summary: The effect of ionomer spatial distribution on oxygen and proton transport in the cathode catalyst layer (CCL) of the proton exchange membrane fuel cell (PEMFC) has been studied. The assumption of a mean spatial distribution for ionomer tends to underestimate cell performance, as the actual spatial distribution leads to higher proton transport resistance but greater oxygen concentration. This study provides guidance for future PEMFC models.
Article
Green & Sustainable Science & Technology
Pablo A. Garcia-Salaberri
Summary: The design and development of proton-exchange membranes (PEMs) for fuel cells and related electrochemical devices is crucial for achieving high performance and durability. PFSA-based PEMs have become the commercial standard due to their high proton conductivity and chemical stability, but there is increasing interest in aromatic HC-based PEMs with PTFE reinforcement. In recent years, the focus has shifted towards the development of hybrid and composite ultra-thin PEMs with customized properties.
SUSTAINABLE MATERIALS AND TECHNOLOGIES
(2023)
Article
Chemistry, Physical
Hong Ren, Xiangchao Meng, Yongli Lin, Zhigang Shao
Summary: The study suggests that catalyst inks containing long-side-chain ionomers show better structural stability after storage compared to those containing short-side-chain ionomers, making it easier to regain initial ink properties.
JOURNAL OF POWER SOURCES
(2022)
Article
Chemistry, Physical
Fengman Sun, Haijun Liu, Ming Chen, Haijiang Wang
Summary: By chemically modifying Pt/C catalyst, we designed a high-oxygen mass-transfer Pt/ionomer interface. The modified membrane electrode assembly (MEA) showed higher voltage at high humidity and reduced oxygen transport resistance. Decreasing the Rionomer of Pt/ionomer interface is the key to improving oxygen transport.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Physical
Hejin Huang, Zhen Cao, Karim R. Gadelrab, Jonathan P. Mailoa, Alfredo Alexander-Katz
Summary: Nafion, a commonly used material for PEFC, faces dehydration and dimensional instability issues in high-temperature, low-humidity environments. This paper proposes a potential solution by introducing nanoscale confinements to Nafion chains. It is found that dual chemistry confinement, consisting of both hydrophobic and hydrophilic confinements, can improve water absorption behavior and reduce dimensional instability of the Nafion membrane.
CHEMISTRY OF MATERIALS
(2021)
Article
Environmental Sciences
Kuan Shiong Khoo, Wen Yi Chia, Kexin Wang, Chih-Kai Chang, Hui Yi Leong, Muhammad Nasrulhazim Bin Maaris, Pau Loke Show
Summary: This review summarizes the application of ionic liquids in high-temperature proton exchange membrane fuel cells, discusses their advantages when combined with polybenzimidazole, and evaluates and discusses the research development and issues of ILs.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Electrochemistry
Chao Lei, Fan Yang, Natalia Macauley, Magali Spinetta, Gerie Purdy, Jasna Jankovic, David A. Cullen, Karren L. More, Yu Seung Kim, Hui Xu
Summary: Different ionomer dispersion solvents have a significant impact on the performance and durability of PEM fuel cells, with non-aqueous solvents showing advantages in morphology and stability of electrode layers.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Polymer Science
Adisak Pokprasert, Patrick Theato, Suwabun Chirachanchai
Summary: Proton transfer in polymer electrolyte membrane is a crucial mechanism in polymer electrolyte membrane fuel cells. This study proposes a method to enhance proton conductivity by aligning proton donor and acceptor polymer chains on the membrane surface through surface-initiated polymerization.
Article
Engineering, Chemical
Shengyang Zhou, Yuyang Cai, Qifeng Zhang, Jifu Zheng, Shenghai Li, Yunqi Li, Suobo Zhang, Yi-hong Ding
Summary: The study presents a novel approach for designing semi-crystalline fluorinated PEMs with high proton conductivity under high temperature and low humidity conditions. The structural characteristics of the PEMs help improve the stability of nanochannels at elevated temperatures and low humidity, showing potential for enhancing fuel cell performance.
JOURNAL OF MEMBRANE SCIENCE
(2021)
Correction
Chemistry, Physical
Isabel Hanghofer, Gunther J. Redhammer, Sebastian Rohde, Ilie Hanzu, Anatoliy Senyshyn, H. Martin R. Wilkening, Daniel Rettenwander
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Inorganic & Nuclear
Maria Gombotz, Alexandra Wilkening, H. Martin R. Wilkening
Summary: This study investigates the ion dynamics of interfacial Li2S in lithium-ion batteries. Nanostructured Li2S was prepared through high-energy ball milling, and its temperature-dependent ionic conductivity was studied using impedance spectroscopy. The results show that ball-milled Li2S exhibits significantly higher ion conductivity and lower average activation energy compared to the unmilled counterpart. Structural disorder, stress, and local distortions are believed to be responsible for these changes in macroscopic transport parameters.
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES
(2022)
Article
Chemistry, Physical
Lukas Ladenstein, Katharina Hogrefe, H. Martin R. Wilkening
Summary: By studying LiHf2(PO4)3 solid electrolytes with different amounts of Ga doping, their ionic conductivity can be optimized, showing potential for application in all-solid-state Li-ion batteries.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Energy & Fuels
Patrick Posch, Sarah Lunghammer, Alexandra Wilkening, Katharina Hogrefe, H. Martin R. Wilkening
Summary: In this study, nucleus-specific Li-7 and Na-23 nuclear magnetic resonance (NMR) spectroscopy was used to investigate the motion processes in mixed-conducting Li4Na (x) Ti5O12 materials. The results show that the diffusivity of Li+ ions increases significantly in the early stages of chemical sodiation, while there is limited data on the diffusion properties of Na+ ions. In addition, the formation of interfacial solid solutions was observed at very low sodiation levels (x = 0.1), and these regions covered almost the entire crystallite area at x = 0.5, enabling facile long-range ion transport.
JOURNAL OF PHYSICS-ENERGY
(2023)
Article
Physics, Applied
N. G. Hallfors, D. Maksimovski, I. A. H. Farhat, M. Abi Jaoude, A. R. Devarajan, K. Liao, M. Ismail, H. Pade, R. Y. Adhikari, A. F. Isakovic
Summary: The combination of nanoscale engineered materials and wearable wireless technologies can revolutionize health monitoring. A composite material called reduced graphene oxide-nylon is developed and tested, showing potential as a sensor material for long-term electrocardiogram (ECG) monitoring. Structural analysis confirms the limited defects in the material, and spectroscopy analysis confirms its electrical and optical properties. The negligible effect of defects and the tunability of properties make it suitable for various sensor applications beyond ECG.
APPLIED PHYSICS LETTERS
(2023)
Article
Electrochemistry
Antonija Ferbezar, Roman Zettl, Harald Fitzek, Bernhard Gadermaier, Ilie Hanzu
Summary: In this study, ionogels based on the UiO-66 type metal organic framework (MOF) were prepared and their conductivity properties were investigated. It was found that UiO-66-NH2-based ionogels showed a promising increase in conductivity in the presence of sodium ions, while UiO-66-(OH)2-based ionogels exhibited the highest conductivity at 293 K.
ELECTROCHIMICA ACTA
(2022)
Article
Chemistry, Physical
Peter Fuerk, Matiss Reinfelds, Ilie Hanzu, Theresa Hartl, Jana B. Schaubeder, Elena Zuccala, Heinz Amenitsch, Thomas Rath, Gregor Trimmel
Summary: Organic photovoltaics are a promising technology for sustainable energy conversion. By synthesizing high-permittivity active layer materials and optimizing them in a bilayer setup, we were able to prevent morphology-related efficiency losses in organic solar cells and increase their efficiency to 5.51%.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Jonas Spychala, H. Martin R. Wilkening, Alexandra Wilkening
Summary: Li2OHCl is a suitable Li+ ionic conductor composed of abundant elements excluding Li. Its low melting point enables easy synthesis methods. However, the clear picture of Li+ self-diffusion is still challenging to prove, as it is suggested to be coupled to OH- rotational dynamics in Li2OHCl.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Maria Gombotz, Caroline Hiebl, Florian Stainer, H. Martin R. Wilkening
Summary: The development of ceramic proton conductors is of great interest due to their potential use in energy storage systems. Li6La3ZrTaO12 (LLZTO) has been found to exhibit rapid Li+ diffusivity. By treating a single crystal in water or glacial acetic acid, mobile Li+ ions can be exchanged with protons, resulting in a mixed proton-lithium ionic conductor. In this study, the diffusion of H+ protons and Li+ ions in the exchanged LLZTO has been investigated using element-specific H-1 and Li-7 NMR spectroscopy. The results show slower long-range Li-7 diffusion but relatively high H+ diffusivity, albeit slower than Li+ dynamics. By measuring spin-lattice relaxation and self-diffusion coefficient D(H) of H+ dynamics, energy barriers and transport properties have been determined, suggesting the potential of designing fast transport pathways for protons in ceramics.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Materials Science, Multidisciplinary
Patrick Bottke, Katharina Hogrefe, Julia Kohl, Suliman Nakhal, Alexandra Wilkening, Paul Heitjans, Martin Lerch, H. Martin R. Wilkening
Summary: The visualization of atomic or ionic jump processes on a nanometer length scale is important for understanding diffusion pathways in solid electrolytes. This study used high-resolution 6Li nuclear magnetic resonance (NMR) spectroscopy to investigate Li+ exchange processes in Li3VF6. The results confirmed the preferred diffusion pathways and provided further insights into ion dynamics between corner-shared Li-bearing polyhedra.
MATERIALS RESEARCH BULLETIN
(2023)
Article
Chemistry, Physical
Alexander Komar, Dirk Wilmer, Martin R. Wilkening, Ilie Hanzu
Summary: The determination of stray capacitance in impedance measuring cells is crucial for studying solid ion conductors. We present a general method that accurately determines stray capacitance and can be applied to various impedance cells or sample holders for temperature conductivity measurements. Experimental calibration on a 2032-type coin cell sample holder demonstrates the reliability of our method for impedance measurements of air sensitive materials. Our method serves as an example of good practice in the field of solid electrolytes, solid state batteries, and dielectric materials investigations.
SOLID STATE IONICS
(2023)
Article
Chemistry, Multidisciplinary
Div Chamria, Christopher Alpha, Ramesh Y. Adhikari
Summary: We have developed a method for assembling and characterizing highly conductive films of composites of phenylalanine and PEDOT:PSS. These films exhibit significantly improved conductivity compared to pure PEDOT:PSS films, and the conductivity can be tuned by adjusting the amount of phenylalanine. Our findings suggest that the improved conductivity is due to the phase separation of PSS chains from PEDOT:PSS globules, which creates efficient charge transport pathways. This technique has the potential for the development of low-cost, biocompatible, and biodegradable electronic materials.
Article
Chemistry, Multidisciplinary
Jian-Fang Wu, Zheyi Zou, Bowei Pu, Lukas Ladenstein, Shen Lin, Wenjing Xie, Shen Li, Bing He, Yameng Fan, Wei Kong Pang, H. Martin R. Wilkening, Xin Guo, Chaohe Xu, Tao Zhang, Siqi Shi, Jilei Liu
Summary: The softness of sulfur sublattice and rotational PS4 tetrahedra in thiophosphates lead to liquid-like ionic conduction, while the existence of such conduction in rigid oxides remains unclear. This study discovers 1D liquid-like Li-ion conduction in LiTa2PO8 and its derivatives, enabled by doping strategies, with low activation energy and short mean residence time of Li ions on interstitial sites. The findings provide principles for the future design of improved solid electrolytes without modifications to achieve stable ionic transport.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Ruvan de Graaf, Yannick De Decker, Victor Sojo, Reuben Hudson
Summary: The ongoing research on the emergence of life focuses on constructing hypothetical environments to produce organic molecules. Mineral catalysts are used in experiments to facilitate the supply of organics that may have produced prebiotic building blocks. However, most studies lack rigorous materials analyses and sub-stoichiometric amounts of metals or minerals, which are necessary to demonstrate the viability of catalysis. Future work should aim to decrease catalyst loading, increase productivity, and conduct rigorous materials analyses to provide evidence of true catalysis.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Katharina Hogrefe, Nicolo Minafra, Isabel Hanghofer, Ananya Banik, Wolfgang G. Zeier, H. Martin R. Wilkening
Summary: This study focused on the impact of cation substitution on Li+ ion dynamics using Li6+xP1-xGexS5I as a model system, revealing that replacing P5+ with Ge4+ not only causes anion site disorder but also allows Li+ ions to occupy initially empty sites between Li rich cages. NMR results showed new Li+ exchange processes in Ge-rich samples with low activation barriers, facilitating rapid ion exchange processes between Li cages.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
