bluuebunny/crossref_metadata_2025 huggingface dataset:
Fe-N-C Oxygen Reduction Catalysts Via Chemical Vapor Deposition in Fluidized Bed Reactor
Authors: Primbs Mathias , Hornberger Elisabeth , Schroeer Pierre , Selve Sören , Strasser Peter
Published: February 2024

Metal nitrogen carbon catalysts (MNC) are an attractive substitute for platinum-based catalysts in the oxygen reduction reaction (ORR) in PEM fuel cells. However, state-of-the-art MNC catalysts still suffer from low activity and instability. Li et al. [1] demonstrated the use of zinc imidazolate frameworks (ZIF-8) in chemical vapor deposition (CVD) to form active sites without unwanted particle formation or additional treatment steps. In this method, gaseous iron chloride exchanges the zinc in the precatalyst to form active sites.

In this work, we introduce a vertical fluidized bed reactor (FBR) for high-scale synthesis of FeNC via CVD, allowing for uniform dispersion of the precatalyst and better zinc-iron exchange. Furthermore, we investigated the influence of differently sized ZIF-8 on the CVD and the formation of the FeNC catalyst.

The final catalysts were characterized for their electrochemical activity in a rotating ring disc setup, their site density via CO-chemisorption, and their respective turnover frequency. The physicochemical characterization includes the analysis of surface area and pore structure via nitrogen physisorption, SEM, and TEM, as well as surface structure and compositional analysis via elemental analysis, ICP-OES, and XPS.

The exchange of Zn was in the range of 90%, resulting in an iron content of 3.8 wt% with only the formation of desired Fe-Nx active sites. STEM-EDX imaging shows an even distribution of iron and nitrogen in the catalyst, with mean particle sizes of 110 nm. In rotating disc electrode experiments with 0.5 M sulfuric acid, mass activities of 0.23 A/g at 0.9 V vs RHE were achieved.

Commercially nano-scaled ZIF-8 with mean particle sizes of 500 nm, synthesized particles with mean sizes of 110 nm were tested, compared to the commercial ZIF-8 Basolite Z1200 with mean particle sizes of 4.9 µm. We could show improved activity in RRDE of the nano-scaled ZIF-8 materials compared to the macro-scaled Basolite.

Applying this highly scalable synthesis method for MNC catalysts could be a viable way to achieve high-performance catalysts for ORR.

[1] Li Jiao, Jingkun Li, Lynne Larochelle Richard, Qiang Sun, Thomas Stracensky, et al.. Chemical vapour deposition of Fe–N–C oxygen reduction catalysts with full utilization of dense Fe–N4 sites. Nature Materials, 2021, 20, pp.1385-1391.
Relationship between Electrode’s Composition, Porosities and Performance on Mesoporous Pt/C Catalysts
Authors: Blanchard Rémi , El harrati Wissam , Manikandan Maidhily , Halim El Mahdi , Durst Julien
Published: February 2024

The FCEVs have earned more attention in the past years, with the urge of finding green alternatives for fuel cells. Very convincing small series vehicles (such as the new Mirai) are spearheads for PEMFC technologies and shows how complex both the system and the MEAs have to be designed. More specifically, in the case of the MEA, the importance of mesoporous carbons as carbon support [1], enabling lower Pt poisoning, but also lower O2 resistance in the catalytic layer [2] has been clearly emphasized. In addition, the porosity distribution of the material was concluded to be both favourable to O2 transport, but also to ionomer film continuity onto the carbon support [2]. However, recent literature also indicated with DFT technologies that the solvent system used (hence the ink formulation) could have a major impact on the performance [3], with possible ionomer penetration in the pore, making sluggish performance with an important bottleneck to oxygen transport.

In this study, we aim at demonstrating how solvents modify the interaction between the ionomer and the mesoporous carbon, with a systematic performance screening in PEMFC configuration (25 cm²), while changing ink formulation or parameters, linking the change of the pore distribution of the coated electrode (N2 adsorption), with the performances.

[1] T. Yoshizumi, H. Kubo, M. Okumura, and T. Motor, SAE inernational, 1–6 (2021).

[2] N. Ramaswamy, W. Gu, J. M. Ziegelbauer, and S. Kumaraguru, J. Electrochem. Soc., 167, 064515 (2020).

[3] N. Kikkawa and R. Jinnouchi, J. Phys. Chem. C, 126, 11518–11528 (2022).
(Invited) Structure-Reactivity Relationship for Pt-Rare Earth Electrocatalysts for Oxygen Reduction Reaction
Authors: Cavaliere Sara , Campos-Roldán Carlos Augusto , Blanchard Pierre-Yves , Chattot Raphael , Rozière Jacques , Jones Deborah J.
Published: February 2024

Alloys of Pt with rare-earth metals (REM) have been demonstrated as one of the most promising candidates with high activity towards oxygen reduction reaction and durability with respect to pure Pt and Pt-alloys with late transition metals1,2. However, due to very low reduction potentials and high oxygen affinity of such elements, the synthesis of Pt-REM nanoalloys by conventional chemical methods is not trivial.

Our group prepared and characterized a series of carbon supported Pt-REM nanocatalysts using a solid-state route3. A systematic investigation of the influence of the type of rare earth metal (Y, Gd, Nd), of the Pt:REM ratio4, and of the post-synthesis treatment5, on the structural, morphological and electrochemical properties of the prepared electrocatalysts was performed. Operando techniques were used to investigate the evolution of the nanoalloys during the electrochemical experiments, providing evidence for the structural transitions and strain dynamics that govern the electrocatalytic activity towards the ORR. For instance, the evolution of the structural, morphological and compositional properties of Pt-Nd nanoalloys occurring during electrochemical activation was studied by online ICP-MS6.

In this presentation an overview of the results obtained on these carbon-supported Pt-REM nanostructured electrocatalysts will be given and the challenges for their application at the PEMFC cathode presented.

J. Greeley et al., Nat. Chem., 1, 552–6 (2009).

C. A. Campos-Roldán, D. J. Jones, J. Rozière, and S. Cavaliere, ChemCatChem, 14 (2022)

Y. Hu, J. O. Jensen, L. N. Cleemann, B. A. Brandes, and Q. Li, J. Am.
Chem. Soc., 142, 953–961 (2020)

C. A. Campos-Roldán et al., ACS Catal., 11, 13519–13529 (2021).

C. A. Campos-Roldán et al., Nanoscale Adv., 4, 26–29 (2022)

C. A. Campos-Roldán et al., sumbitted.

The research leading to these results has received funding from the IMMORTAL project, which receives funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under Grant Agreement No. 101006641. This Joint Undertaking receives support from the European Union's Horizon 2020 research and innovation programme, Hydrogen Europe and Hydrogen Europe Research.
Covalent Crosslinking of High-Density Polyethylene Trimethylammonium-Based Radiation-Grafted Anion Exchange Membranes for Reduced Water Uptakes and Swelling
Authors: Periasamy Arun Prakash , Bance-Souahli Rachida , Whelligan Daniel K , Varcoe John R
Published: February 2024

Anion exchange membranes (AEMs) are polymer membranes of varying thickness (10 - 50 µm) with covalently bound quaternary ammonium cations, which have been evaluated in fuel cells (AEMFCs) and green hydrogen electrolysis.1,2 Radiation-grafted AEMs made from high-density polyethylene (RG-HDPE) with ca. 30 microns hydrated thickness exhibit high hydroxide conductivities, promising mechanical stabilities, and high AEMFC performances.1,3 The enhanced water transport properties is hypothesized to be from nano and microscale level structural and morphological changes.3 Our best performing ultrathin RG-HDPE films exhibited excellent conductivity and AEMFC performance retention over the 400 h.3 However, the water uptake of RG-HDPE film is ca. 150%, hence, it is important to add a controlled amount of crosslinking.4-7

In previous studies of radiation-grafted membranes for use in reverse electrodialysis, crosslinking + amination was achieved by using a heated amination fabrication step involving a mixture of liquid, high boiling point mono-amines (such as N-methylpiperidine) and a crosslinking diamine (such as N,N,N',N'-tetramethyl-1,6-hexane diamine - TMHDA).8 However, a thermal method is not viable or safe when using the commonly supplied aqueous solutions of dissolved trimethylamine (TMA) gas. This presentation will discuss a variety of approaches, to target controlled TMHDA-crosslinking of TMA-based RG-AEMs, targeting reduced water uptakes and swelling with retention of ion conductivity (Figure 1). The most promising approach involved two steps with the initial amination of the poly(VBC)-grafted HDPE intermediate membranes using a sub-stoichiometric amount of TMHDA. Square wave voltammetry analysis of the solution recovered from amination step 1 confirmed complete reaction of the added TMHDA. In the second step, the membranes were then quickly [important] reacted with aqueous TMA to complete the amination process. TMA can displace TMHDA-based head-groups after long step 2 amination times, hence, we emphasize the use of short TMA amination times in the second step.

References

[1] Wang, Lianqin, et al., J. Mater. Chem. A, 6, 15404 (2018).

[2] Ferriday, T. B., and Peter H. Middleton, Int. J Hydrogen Energy, 46, 18489 (2021).

[3] Wang, Lianqin, et al., Energy Environ. Sci.,
12, 1575 (2019).

[4] T Willson, Terry R., et al., Sustain. Energy Fuels, 3, 1682 (2019).

[5] Iravaninia, Mona, et al., Int. J hydrogen energy 42, 17229 (2017).

[6] Hossain, Md Masem, et al., J Power Sources,
390, 234 (2018).

[7] Xu, Shuai, et al., Mater. Chem., 22, 13295 (2012).

[8] Bance-Soualhi, Rachida, et al., J. Mater. Chem. A,
9, 22025 (2021).

Figure 1
(2022-2023 ECS Toyota Young Investigator Fellowship)
Enhanced Water Electrolysis Using Layered Coaxial Nanowire Electrodes
Authors: Arman Tanvir Alam , Yilmaz Abdurrahman , O. Godoy Andres , Liyanage Wipula Priya Rasika , Routkevitch Dmitri , Komini Babu Siddharth , Jankovic Jasna , Pasaogullari Ugur , Spendelow Jacob S.
Published: February 2024

Novel electrocatalytic approaches are urgently needed to increase the energy efficiency and decrease the cost of hydrogen production by PEM water electrolyzers. Recently, we developed a novel catalytic platform, the layered coaxial nanowire electrode (LCANE), which enables PEM water electrolyzers with higher energy efficiency and reduced usage of precious metal catalysts. Electrolyzers based on the LCANE approach use a thin film of IrO2-decorated Pt that is intimately interfaced with an ionomer membrane in the form of vertically-aligned coaxial nanowires. Each nanowire consists of a Pt shell encapsulating an ionomer core, with the Pt shell further decorated by IrO2 clusters. The top region of each nanowire bends to form a layer of in-plane aligned Pt/IrO2 nanowires, providing excellent in-plane electronic conductivity. This unique catalyst/electrode geometry offers several key advantages. By localizing ionomer within the nanowire core, the exterior surface of the catalyst remains free from ionomer, eliminating thin-film transport barriers and preventing catalyst poisoning by ionomer adsorption. The vertically aligned sections of the nanowires provide non-tortuous transport of reactants and products, with abundant pore space for facile access of water and removal of oxygen. Close integration of catalyst and ionomer provides improved proton access and eliminates stranding of catalyst. By incorporating catalyst in the form of a thin film and replacing some of the Ir with Pt, lower Ir loading (as low as 0.1 mg/cm2) is achieved without sacrificing surface area or performance.

Acknowledgment

This work was supported by the ECS-Toyota Young Investigator Fellowship and by the Laboratory Directed Research and Development program at Los Alamos National Laboratory.
Visualization of Oxygen Bubbles on a Flat Ionomer-Coated Platinum Electrode
Authors: Suwa Hideki , Kanemoto Ryo , Toyama Kohei , Kishi Sota , Araki Takuto
Published: February 2024

To improve the performance of polymer electrode membrane electrolyzers, it is necessary to grasp oxygen transport from the reaction site. This paper presents a visualization study which examines the effect of ionomers on the behavior of oxygen bubbles generated from the catalyst covered with ionomers. For the sake of visualization, a flat electrode was fabricated on a glass plate as shown Fig.1 (a). The reaction area was plated with platinum and covered entirely with ionomer using a spin coater.

As shown Fig.1 (b), oxygen bubbles generated on ionomer surface were successfully captured with a high-speed camera. As shown Fig.1 (c), (d) the post visualization by electron microscopy with EDX showed that there were no significant cracks and damages on the ionomers. In other words, oxygen bubbles are generated on the ionomer surface without an apparent three-phase boundary (i.e., catalyst-ionomer-water). This suggests oxygen generated on the Pt surface was transported through the ionomer layer. The three-phase boundary may not be mandatory for the catalyst layer. The results presented in this research can provide better understanding of oxygen transport properties inside catalyst layer, thereby contributing to the future optimization of the structural design of catalyst layers.

Acknowledgement

This study was based on results obtained from the Development of Fundamental Technology for Advancement of Water Electrolysis Hydrogen Production in Advancement of Hydrogen Technologies and Utilization Project (P14021) commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Fig.1 (a) Flat electrode on a glass plate, (b) Figure of the oxygen bubbles when electrolyzing, Element mapping of (c) Platinum and (d) Fluorine

Figure 1
Manufacturing Challenges, Opportunities, and Successes for PEM Electrolysis at Scale
Authors: Capuano Christopher B. , Ayers Katherine E. , Fortiner Serafina , Ouimet Ryan
Published: February 2024

Hydrogen generation via electrolysis has gained much attention internationally as not only a sustainable source of fuel for the transportation, but as a carrier of energy to capture stranded renewable energy due to the carbon-free chemical cycle and response characteristics of the technology. The barrier to entry preventing this technology from being widely adopted is the overall cost associated with both the upfront capital expense as well as the operating cost incurred over the product life. The majority of this cost is driven by 1) low electrical efficiencies due to the high ohmic resistance of thicker membranes required by electrolysis systems to electrochemically compress generated hydrogen for storage and the overpotential associated with the water splitting oxygen evolution reaction (OER) catalysts typically used, 2) high cost of system and cell stack materials, which need to be durable for up to 100,000hrs at potentials approaching 2V in both reducing and oxidizing environments, and 3) the lack of a robust supply chain for high volume manufacturing to further drive down cost through economies of scale.

With 95% of hydrogen currently being produced through the reformation of cheap natural gas, significant cost reductions are necessary for electrolysis to become a viable alternative to the incumbent. Commercial proton exchange membrane (PEM)-based electrolysis has reached scales of several hundred kg/day, providing a relevant pathway for industrial scale hydrogen generation with tremendous opportunity for continuing cost reduction by leveraging system and manufacturing scaling laws and advancements in PEM fuel cell materials, manufacturing, and analysis tools. Order of magnitude improvements in some of the highest cost elements are easily achievable and with more research funding being directed towards hydrogen production, the realization of these reductions is occurring at a faster rate. While many improvements in stack design and materials of construction have been identified and implemented, there are still numerous opportunities to explore that would move electrolysis towards a viable, cost-effective alternative to natural gas reformation. This talk will describe some of the areas of success, where research is still needed, and ultimately how each of these improvements translate into cost and the path to reformation parity.
Coupled Simulation of Chemical Membrane Degradation and Oxygen Crossover in PEM Water Electrolysis
Authors: Eckert Christoph , Trinke Patrick , Bensmann Boris , Hanke-Rauschenbach Richard
Published: February 2024

The membrane of polymer electrolyte membrane water electrolysis (PEMWE), as one of the lifetime limiting components, does not only have an impact on performance, but also plays an important role for safety issues over time. Membrane thinning is a key phenomenon caused by chemical membrane degradation and directly affects the conductivity and gas crossover. Therefore, a chemical membrane degradation model based on Fenton equations [1,2] coupled with a gas crossover model [3] is presented in this work. The presence of Oxygen at cathode side is considered by oxygen crossover, which is strongly enforced by supersaturation effects. Specifically, this cathode-side oxygen is conducive to hydrogen peroxide formation. In interaction with metal ions, e.g. iron, from the feed water, which partially migrate through the membrane, hydroxyl radicals can be formed. These attack the polyfluorinated sulfonicacid (PFSA) membrane at different points, releasing sulfon acid head groups (SO3H-) and fluride ions (F-), which can be measured as sulfur release rates (SRR) and fluride release rates (FRR) in the effluent water, respectively. The degradation model provides concentration profiles for the relevant species involved in the process, which, e.g., influence the thickness and conductivity of the membrane via structure-function relations. In particular, the changed thickness again influences the crossover effect, which itself represents an input for the degradation model. Through this coupling, both models can be updated at specific times. Implications of the model-based analysis on the mechanistic understanding of chemical membrane degradation by radical attack in PEMWE are discussed. Furthermore, the model results can be verified and calibrated by experimental data in combination with adapted accelerated stress tests (AST) and also encourage their enhancement.

References

[1] Frensch, S. H., Serre, G., Fouda-Onana, F., Jensen, H. C., Christensen, M. L., Araya, S. S., and Kær, S. K. (2019). Impact of iron and hydrogen peroxide on membrane degradation for polymer electrolyte membrane water electrolysis: Computational and experimental investigation on fluoride emission. Journal of Power Sources, 420:54–62.

[2] Frühwirt, P., Kregar, A., Törring, J. T., Katrašnik, T., and Gescheidt, G. (2020). Holistic approach to chemical degradation of nafion membranes in fuel cells: modelling and predictions. Physical Chemistry Chemical Physics, 22(10):5647–5666.

[3] Trinke, P., Bensmann, B., and Hanke-Rauschenbach, R. (2017). Current density effect on hydrogen permeation in pem water electrolyzers. International Journal of Hydrogen Energy, 42(21):14355–14366
Enhancing Durability of Polymer Electrolyte Membrane Water Electrolyzer through Incorporation of Gas Recombination Catalyst in Membrane
Authors: Li Kui , Khedekar Kaustubh , Wilson Mahlon , Spendelow Jacob S. , Komini Babu Siddharth
Published: February 2024

Hydrogen will become a critical component of the future energy landscape driven primarily by the growing use of renewable energy sources. Polymer electrolyte membrane water electrolyzer (PEMWE) is a superior technology to facilitate hydrogen production from renewable electricity. However, durability remains a significant challenge for the widespread commercialization of electrolyzers.1 Cross-over of H2 from cathode to anode could lead to explosive mixtures in the anode causing safety concerns during operation. Hydrogen crossover also impacts the durability of the anode catalyst.2 Hydrogen permeation from the cathode to the anode through the membrane reduces the anodic Ir catalyst to a low valence state leading to increased dissolution of the Ir catalyst at a high cell voltage. Utilizing thin membranes (~50µm) can improve the electrolyzer system’s efficiency but also increase the hydrogen permeation, particularly at high pressures.

In this study, we present a methodology to incorporate platinum as a gas recombination catalyst (GRC) layer into commercial membranes, significantly reducing hydrogen permeation rates and mitigating anode catalyst degradation. Membranes with GRC can mitigate the degradation of PEMWE, leading to more efficient and durable PEM electrolysis systems for hydrogen production. The methodology developed enables higher control of the GRC layer properties (Pt particle size and location in the membrane). Ex-situ measurement of hydrogen permeation, shown in Figure 1, indicates a significant reduction in the permeation rate for GRC incorporated NR 212. This study presents a systematic electrochemical evaluation of anode degradation in PEMWE with and without GRC in the membrane using accelerated stress tests. The durability of the GRC during long-term operation is also presented.

Acknowledgment

This research is supported by the U.S. Department of Energy (DOE) Hydrogen and Fuel Cell Technologies Office through the Hydrogen from Next-generation Electrolyzers of Water (H2NEW) consortium.

References

1. Tomic, A. Z., Pivac, I., Barbir, F., Journal of Power Sources (2023) 557

2. Rheinlander, P. J., and Durst, J., Journal of the Electrochemical Society (2021) 168 (2)

Figure 1
Manufacturable Microporous Layers on Sintered Titanium for PEM Electrolysis Applications
Authors: Hill Alex , Goliber Daniel , Gosselin Sean , Tsaknopoulos Derek , Kar Piyush , Papandrew Alexander B
Published: February 2024

Renewed interest in green hydrogen has prompted a re-examination of the components of proton-exchange membrane water electrolyzers to improve stack durability and lower net hydrogen cost. A key component identified as a driver of cell performance and durability is the anode porous transport layer (PTL). The PTL dictates electrical resistance between anode and flow field, manages two-phase flow at the anode interface, and sinks heat from the electrolysis reaction.

Efforts to optimize the PTL have typically focused on limiting titanium passivation and optimizing delivery of water and discharge of oxygen at the anode. However, recent work has shown another important effect related to the contact area of the PTL with the anode catalyst layer. Multiple investigators have shown that highly flat and smooth PTLs enhance cell durability, particularly in the case of low anode catalyst loadings (< 0.5 mgIr/cm2). In those studies1–5, commercial PTLs were modified to obtain more uniform surfaces. In some cases this is effected by attachment of finely structured microporous layers (MPLs) that improve catalyst utilization and eliminate localized heating.

An integrated manufacturing approach is required to enable commercial adoption of advanced PTLs featuring microporous layers. In this contribution, we investigate multiple routes and materials systems for obtaining manufacturable MPLs. We assess the relative merits of each method with respect to feasibility and resultant component characteristics, and validate ex situ characterization with single-cell electrolyzer durability testing using catalyst-coated membranes with low Ir loadings.

References

(1) Lettenmeier, P.; Kolb, S.; Sata, N.; Fallisch, A.; Zielke, L.; Thiele, S.; Gago, A. S.; Friedrich, K. A. C Energy Environ. Sci.
2017, 10 (12), 2521–2533. https://doi.org/10.1039/C7EE01240C.

(2) Kang, Z.; Yang, G.; Mo, J.; Yu, S.; Cullen, D. A.; Retterer, S. T.; Toops, T. J.; Brady, M. P.; Bender, G.; Pivovar, B. S.; Green, J. B.; Zhang, F.-Y. Int. J. Hydrog. Energy
2018, 43 (31), 14618–14628. https://doi.org/10.1016/j.ijhydene.2018.05.139.

(3) Lee, J. K.; Lee, C.; Fahy, K. F.; Kim, P. J.; LaManna, J. M.; Baltic, E.; Jacobson, D. L.; Hussey, D. S.; Stiber, S.; Gago, A. S.; Friedrich, K. A.; Bazylak, Energy Convers. Manag.
2020, 226, 113545. https://doi.org/10.1016/j.enconman.2020.113545.

(4) Schuler, T.; Ciccone, J. M.; Krentscher, B.; Marone, F.; Peter, C.; Schmidt, T. J.; Büchi, F. N. Adv. Energy Mater.
2020, 10 (2), 1903216. https://doi.org/10.1002/aenm.201903216.

(5) Lee, J. K.; Schuler, T.; Bender, G.; Sabharwal, M.; Peng, X.; Weber, A. Z.; Danilovic, N. Appl. Energy
2023, 336, 120853. https://doi.org/10.1016/j.apenergy.2023.120853.

Figure 1
Understanding Porous Transport Layer Structure-Property-Performance Relationships in PEM Water Electrolyzers
Authors: Wrubel Jacob A , Ware Sam , Young James L. , Padgett Elliot , Hu Leiming , Rice Robin , Bender Guido
Published: February 2024

Low temperature electrolysis (LTE) is a very promising technology to help with the decarbonization of the energy sector through the production of green hydrogen from renewable energy sources. The DOE has recently launched the first Energy Earthshot targeting the reduction of clean hydrogen cost by 80% to $1 per 1 kg H2 produced in 1 decade. To reach such ambitious targets the technology development needs to consider both capital expenditures (CAPEX) such as material and component costs and their lifetimes, as well as operational expenditures (OPEX) such as cell performance and efficiency. One component that touches on either expenditure is the porous transport layer (PTL). The PTL provides various key functions within an electrolysis cell/stack. It provides transport pathways for electrons, water and gas, and mechanical support for the membrane. Its interface with the catalyst layer is crucial with regards to the limitation of ohmic overpotentials, but also heat transport within the cell. PTLs are currently fabricated from sintered Ti materials that are required to be coated with a PGM material when operated with low loading catalyst layers. Multi-layer PTL materials may further improve cell performance and enable the thrifting of catalyst loadings and the utilization of thin membrane materials. This presentation will introduce the various functionalities of the PTL and highlight research and development efforts including those of DOE’s H2New Consortium and NREL. Specifically impacts of PTL morphology, PTL coatings, and PTL/catalyst layer interactions will be discussed.
(Digital Presentation) Dynamic Thermal Detection of Water Electrolyzer with Dual-Layer Characteristic Temperature Based on IR
Authors: Shangguan Zixuan , Zhang Cunman
Published: February 2024

As the prevalence of water electrolysis systems continues to expand, increased attention has been placed on the dynamic thermal detection of the electrolyzer. Presently, the scope of dynamic thermal detection for water electrolysis systems is limited to solely the temperatures at the inlet and outlet. This study propounds a novel dual-layer characteristics temperature (DLCT) model for the purpose of water electrolyzer temperature monitoring. The DLCT model addresses two significant issues of the dynamic thermal detection of the WEE: characteristic temperature extraction difficulty and signal perturbation caused by auxiliary factors. The first layer of multi-gaussian distribution (MGD) regression in the DLCT model quantifies the sectional temperature of the electrolyzer surface and produces numerous potential characteristic temperatures (CT). These temperatures are subsequently assigned to each section and are then conveyed to the second layer of linear regression, which provides an incisive quantized temperature variation pattern for the electrolyzer surface temperature distribution. Importantly, the DLCT model requires no supplementary modifications to the water electrolysis system or the installation of temperature sensors within or on the surface. By employing the DLCT model during dynamic operation, the ability to monitor the temperature of the electrolyzer comprehensively is improved, the temperature distribution of the electrolyzer can be quantized and richer insights regarding the surface temperature distribution can be gained, promoting better thermal uniformity, as well as pin-pointing the potential hot spot. Hence this method can also be used for structure design to produce better uniformity. The dynamic temperature detection results under different operating conditions are analyzed, and it can be concluded that the operating parameters, especially the lye circulation flow, can greatly influence the temperature distribution uniformity of the electrolyzer significantly. In conclusion, the DLCT model effectively handles the two primary challenges in dynamic thermal detection of water electrolysis systems by providing global and sectional characteristic temperature readings, enabling electrolyzer to be monitored holistically. So that future improvement regarding both structural and operational optimization can be conducted in improving the thermal uniformity.

Figure 1
(Invited) Correlation of Exciton and Charge Carrier Dynamics with the Performance of Metal Halide Perovskite Solar Cells
Authors: Tachibana Yasuhiro
Published: February 2024

Perovskite solar cells have been recognized as a newly emerging solar cell with the potential of achieving high efficiency with a low cost fabrication process. In particular, facile solution processed cell fabrication facilitated rapid development of optimum cell structure and composition. Over the last few years, the cell efficiency has exceeded 25%.

Highly efficient charge transfer reactions in addition to high charge separation efficiency and swift charge transport with minimum charge recombination are required to improve solar cell performance. Intensive studies have been focused on monitoring photo-induced exciton formation and charge dissociation, charge transport and interfacial charge transfer dynamics including interfacial charge recombination in perovskite solar cells.[1-5] Several parameters have been identified to influence these charge carrier dynamics, and therefore the solar cell performance.[1-5] Clarifying these parameters is extremely important to understand the charge transfer mechanisms to further improve solar cell performance.

In this presentation, we will present parameters controlling charge dissociation in metal halide perovskites and their charge separation and recombination dynamics at the perovskite interfaces employing a series of transient absorption and emission spectroscopies. Correlation of the key parameters controlling the exciton and charge carrier dynamics with the solar cell performance will be discussed [1-5].

This work was partly supported by JSPS KAKENHI Grant (19H02813) and (22H02182), and the Collaborative Research Program of Institute for Chemical Research, Kyoto University (grant number 2023-45 and 2022-99), Japan. We would like to acknowledge supports from the Australia-Japan Foundation for the international collaborative project. We also acknowledge supports from ARC LIEF fund (LE200100051 and LE170100235), Australia and School of Engineering in RMIT University, and Forefront Research Center, Faculty of Science at Osaka University.

References

[1] S. Makuta, M. Liu, M. Endo, H. Nishimura,A. Wakamiya and Y. Tachibana, Chem. Commun., 52 (2016) 673 - 676.

[2] M. Liu, M. Endo, A. Shimazaki,A. Wakamiya and Y. Tachibana, J. Photopolym. Sci. Technol.
30 (2017) 577-582.

[3] M. Liu, M. Endo, A. Shimazaki,A. Wakamiya and Y. Tachibana, J. Photopolym. Sci. Technol., 31 (2018) 633-642.

[4] M. Liu, M. Endo, A. Shimazaki,A. Wakamiya and Y. Tachibana, ACS Appl. Energy Mater., 1 (2018) 3722-3732.

[5] M. Liu, H. Liu, S. R. Padmaperuma, M. Endo, A. Shimazaki,A. Wakamiya and Y. Tachibana, J. Photopolym. Sci. Technol., 32 (2019) 727-733.
Fabrication Knowledge and Techniques for Multiporous-Layered-Electrodes Perovsekite Solar Cells (MPLE-PSCs)
Authors: Ito Seigo
Published: February 2024

Multiporous-Layered-Electrodes Perovsekite Solar Cells (MPLE-PSCs) shows high stability (for 7000 h at 100 degree C; for 10,000 h under 1-Sun irradiation, for 3,000 h at 85%RH-85 degree C), adequate efficiency (11.5% by large modules), and low cost by fully-printed fabrication systems. In oder to fabricate good modules of MPLE-PSCs, good techniques and knowledges should be gathered up for the commercialization. In this conference, our group will show the efforts for the cost-effective commercially-available fully-printed MPLE-PSCs.
Effect of the Magnetostriction Induced on the Crystalline Structure of Nanoparticulate TiO2 Photoanodes and Their Relationship with the Photovoltaic Response of Black-Dye Sensitized Solar Cells
Authors: Valdez Nava Jesus Israel , Pérez-Nava Isa Fernanda , Bustos Erika , García-Melo José Alberto , Manriquez Juan
Published: February 2024

The study of ferromagnetism (FM) in semiconductor oxides having non-cubic crystalline structures (e.g. TiO2) is attractive due to their applications in spintronics [1]. FM can be activated in TiO2 nanomaterials by promoting oxygen vacancies (VO) located in paramagnetic defected sites Ti3+VOTi4+. In this context, the VO can induce in Ti3+-doped TiO2 structures remarkable magnetic anisotropy energy (MAE) of 6.51x106 erg/cm3, thus indicating the magnetic saturation (Ms) should be achieved by applying external magnetic fields (MFs) of ~425 gauss [2,3]. Therefore, magnetostriction can be observed in ferromagnetic TiO2 films containing Ti3+VOTi4+ sites as a phenomenon in which their dimensions and shapes are changed when they are magnetized. In this work, black dye-sensitized solar cells (BD-SSC) were prepared using TiO2 nanoparticle films enriched by Ti3+VOTi4+ sites, to gain an understanding of the effects of magnetostriction on the photovoltaic responses of BD-SSC. In this way, photocurrent density-cell potential plots were obtained for the BD-SSC in the absence and presence of MFs having intensities of 125, 250, 500, 1000, and 2000 gauss. MFs lines were parallel applied to the surface of the BD-sensitized TiO2 photoanodes. Our results indicated that the photogenerated electron transport through the dyed TiO2 photoanodes was not limited by electron transfer to I3
- anions at the electrolyte in the absence or the presence of MFs, because all the values for the open-circuit potential (-Eoc
~ 0.553±0.014 V) remain constant. On the contrary, the obtained values for the short-circuit current density Jsc
and the global conversion efficiency, revealed that both parameters increased as a function of the MFs intensities, thus indicating that the magnetic lines were responsible for decreasing the degree of disorder (0<b<1) of the electron-traps at the intra-bandgap state's distribution of the TiO2 film (Jsc
is proportional to Q1/
b where Q is the number of trapped electrons) [4,5].

[1] M. Stiller et al., Front. Phys., 11(2023)1124924.; [2] D. Kim et al., J. Phys.: Condens. Matter, 21(2009)195405.; [3] B. Shao et al., J. Appl. Phys., 115(2014)17A915. [4] N. Kopidakis et al., J. Phys. Chem. B, 107(2003)11307. [5] J. van de Lagemaat et al., J. Phys. Chem. B, 104(2000)4292.

Acknowledgements

The authors thank the National Council for Science and Technology (CONACyT) Mexico for the funding support (grants CB No. 258789 and FOINS No. 3838). JIVN thanks CONACyT for his doctoral fellowship support (grant No. 893260).
The Nanostructured Future of Electrolytes
Authors: Mariani Alessandro , Liu Xu , Han Jin , Varzi Alberto , Passerini Stefano
Published: February 2024

Lithium-ion and lithium-metal batteries with cobalt-free high-energy cathodes, as well as the newly emerging batteries employing post-lithium ions as charge carriers, are a few topics tackled in recent years for the development of batteries with higher energy density, lower cost, and improved sustainability. While all of them could (and will) be improved over time, electrolytes are prominent because of their ease of adapting to current technologies. Conventional organic electrolytes are usually flammable, toxic, and harmful to humans and the environment. For these reasons, over the years, several alternatives have been proposed. Ionic Liquids1 are promising from a safety point of view, being non-volatile and non-flammable, but they are usually fluorinated to meet specific performance standards. Another sustainable and cost-efficient approach is represented by the Water-in-salt electrolytes (WiSEs)2,3, given that the used salt is sustainable itself. Finally, the newest approach is to tackle the solubility properties of salts to obtain locally concentrated electrolytes using non-solvating solvents4. For all of the proposed new technologies, their impressive properties seem to emerge from the peculiar structural organizations of the species in the system. Therefore, employing experimental (SAXS and Raman) and computational (MD and DFT) techniques to comprehensively understand how the chemical species interact in such systems, is mandatory to further progress in the research.

Figure 1: a) Snapshot of the simulation box of a Locally Concentrated electrolyte. The ionic liquid comprise the worm-like structures, the solvent is only depicted on the left side as a transparent medium. b) coordination numbers as a function of salt concentration in a Water-in-salt electrolyte. c) X-ray scattering patterns for ionic liquid electrolytes and locally concentrated ionic liquid electrolytes at two different temperatures (20 °C top, and -20 °C bottom).

References

1 J. S. Wilkes, A short history of ionic liquids—from molten salts to neoteric solvents, Green Chemistry, 2002, 4, 73–80.

2 L. Suo, F. Han, X. Fan, H. Liu, K. Xu and C. Wang, ‘water-in-Salt’ electrolytes enable green and safe Li-ion batteries for large scale electric energy storage applications, J Mater Chem A Mater, 2016, 4, 6639–6644.

3 J. Han, A. Mariani, S. Passerini and A. Varzi, Energy Environ Sci, 2023, https://doi.org/10.1039/D2EE03682G

4 X. Liu, A. Mariani, H. Adenusi and S. Passerini, Angewandte Chemie - International Edition, 2023,https://doi.org/10.1002/ange.202219318.

Figure 1
The “Buffer Layer” an Improved Electrode-Electrolyte Interface for Solid-State Batteries
Authors: Schmidt Gregory
Published: February 2024

Solid-state lithium batteries are broadly accepted as promising candidates for application in the next generation of EVs as they should offer safer and higher-energy-density batteries. Nonetheless, their development is impeded by many challenges, including the resistive electrode–electrolyte interface originating from the removal of the liquid electrolyte that normally permeates through the porous cathode and insures efficient ionic conductivity through the cell. One way to tackle this challenge is by formulating composite cathodes containing solid ionic conductors in their structure but this approach will require the conductors to exhibit chemical stability, electrochemical stability, flexibility, adhesion and is therefore limited to some materials. Recently, Arkema developed a technology called buffering layer which allows to transform any conventional porous electrode into a catholyte. This organic layer has a very high ionic conductivity at room temperature, is compatible with all active materials and can be processed with conventional Gigafactory equipment. Moreover, this layer helps protect the solid ionic conductor from the cathode and anode materials. During this presentation, the manufacture and the electrochemical performance of this layer for different systems of cathode and anode will be discussed.
Electrochemical and Thermal Evolution of P2 Na2/3MnO2
Authors: Thilakarathna Bopitiye Dilan Krishna Kumara , Brand Helen , Sharma Neeraj
Published: February 2024

The exploration of alternatives for lithium-ion batteries is an ongoing process due to the limited availability and high cost of lithium. Sodium-ion batteries (NIBs) have emerged as a promising candidate, as they have the potential to be cost-effective due to the high abundance of sodium in the Earth's crust. The cathode material, hexagonal (P2) Na2/3MnO2 is an excellent cathode candidate in terms of cost and sustainability, but its electrochemical performance is impacted by structural phase transitions during cycling. In this study, the electrochemical-temperature-dependent phase diagram of P2 Na2/3MnO2 is investigated using synchrotron X-ray powder diffraction. The structure at various states of charge is determined and their thermal evolution is evaluated. Despite the different states of charge, all materials were found to convert to cubic MnO at about 550°C. This talk will showcase the link between electrochemistry and crystallography.
How Reference Electrodes Improve Our Understanding of Degradation Processes in Half and Full-Cell KIB Setups
Authors: Panasenko Iurii , Jeschull Fabian
Published: February 2024

For the last decade, the search for suitable alternatives for Li-ion batteries (LIBs) has steeply increased. While elements such as lithium and cobalt, are in high demand for LIBs, they could soon be replaced by less costly and more abundant elements1. One attractive alternative is potassium-ion batteries (KIBs) because of the abundance of potassium resources, and the lower standard electrode potential of K/K+ compared to lithium2.

For characterization of KIB materials can be used same approaches as for LIB. An exception to that is describing electrochemical behavior, especially in a half-cell. One of the most important challenges for KIBs is a reliable 3-el setup with a stable and reproducible reference electrode (RE). Without a RE, the only possibility to independently quantify the anode and/or cathode impedance is the disassembly of multiple cells and the recombination of the identical anode or cathode pairs in symmetrical cells3. While using a metallic reference electrode is a practical solution for LIBs (using Li metal), the high reactivity of K renders the metal unsuitable as a reference electrode in KIBs.

In this study, we outline our research on stable and reliable reference electrodes and compare several established approaches, specifically K-metal, a partially discharged Prussian white (K2Fe[Fe(CN)6]) and a more classic Ag/AgCl redox couple. Except for battery research, Ag|AgCIsat REs are commonly used in non-aqueous media in electrochemistry and offer the advantage of comparatively high chemical inertness, unlike K-metal or cathode-type RE. It was found that the evolution of degradation products from K-metal also induced significant drifts on a partly charged cathode RE (Fig. a), thus excluding both as reliable RE systems.

In our revised cell design, the Ag|AgCIsat reference electrode was integrated into a thin-layer battery compartment. With this 3-electrode configuration half and full cell experiments, previous 2-electrode tests were revisited. So, the only way to compare the behavior of electrodes in half in full is to have stable and chemically passive RE which is Ag/AgCl. With this setup we were able to study the impact of electrolyte additives on the electrode reactions in more detail and pinpoint cut-off limits in graphite/ K2Fe[Fe(CN)6]. For example, in our experiments it was observed how graphite electrodes degrade under the influence of the DTD (1,3,2-Dioxathiolane 2,2-Dioxide) additive(Fig b).

References:

Komaba, S., Hasegawa, T., Dahbi, M. & Kubota, K. Electrochem. commun.
60, 172–175 (2015).

Kubota, K., Dahbi, M., Hosaka, T., Kumakura, S. & Komaba, S. Chem. Rec.
18, 459–479 (2018).

Linsenmann, F., Pritzl, D. & Gasteiger, H. A. A J. Electrochem.
Soc.
166, A3668–A3674 (2019).

Costard, J., Ender, M., Weiss, M. & Ivers-Tiffée, E.. J. Electrochem. Soc.
164, A80–A87 (2017).

Figure 1
(Invited) Pt-Modified Aluminide Coatings for Ni-Base Single Crystal Superalloy
Authors: Jiang Yiming , Li Shuai , Liu He , Bao Zebin , Zhu Shenglong , Wang Fuhui
Published: February 2024

Single phase (Ni,Pt)Al coating has been widely employed as state-of-the-art bondcoat for protecting hot-sectional components in commercial aero engines, especially for the parts made of Ni-base single crystal (SX) superalloys. For high temperature protective coating serving on SX superalloy, two interfaces are vitally essential for acquiring reliably long service life: the interface growing thermally-grown oxide (TGO) and the interface connecting coating and substrate alloy.

Normally, the excellent performance of PtAl coating derives from high Al content and the incorporation of Pt, which ensures formation of exclusively adherent oxide scale, α-Al2O3. To further improve the performance of Pt-modified aluminide coating, in present study reactive elements are introduced using co-electroplating method. Compared with singular doping, co-doping of Hf-Y demonstrated superior oxidation resistance. The oxide scale growth rate and spallation tendency of Hf-Y co-doped (Ni,Pt)Al coating were much smaller, as well as the surface rumpling extent. Besides, the grain size of Hf-Y co-doped (Ni,Pt)Al coating was finer than that of Hf- or Y- doped coatings in as-received state, indicating the capability of grain refinement. With the benefits of RE co-doping, the desirably thin/smooth TGO is thus accessible for Pt-modified aluminide coatings.

The other issue is the element interdiffusion at high temperature, which would affect the mechanical property of SX superalloy. According to Fick′s law of diffusion,
J

Al

= -
D

Al

·
δμ

Al

/

δ

x

,to reduce diffusion coefficient (
D

Al

) or chemical potential (
δμ

Al

/

δ

x

) would both decrease the diffusion extent (
J

Al

). Therefore, two strategies are employed: adding a diffusion barrier between coating and substrate, or designing a γʹ-PtAl coating. The performance of these modified aluminide coatings are evaluated in high temperature oxidation test. At last, doping behavior of some elements were explained by First-Principle Calculations.