bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Investigation of Halide Solid Electrolytes for Na-Based Batteries
Authors: Arraghraghi Hafssa , Bianchini Matteo
Published: February 2024

Significant scientific and economic challenges are presented by developing battery systems with increased energy storage capacity. Geopolitical issues might pose supply chain risks for lithium (Li)-ion batteries, which are frequently used in portable electronics. As an alternative, sodium-ion batteries (NIBs), have drawn attention from researchers all over the world due to the perspective of being lower cost systems[1]. In comparison to lithium-ion batteries, solid-state sodium-ion batteries (SSSBs) promise as a safe, scalable, and environmentally friendly alternative. For the production of robust and adaptable SSSBs, the development of highly conductive, electrochemically stable, and chemically stable solid electrolytes (SEs) is essential [2]. With greater durability, adaptability, and safety, solid-state batteries with inorganic solid electrolytes are being heavily investigated as safer and perhaps more energy-dense alternatives to liquid electrolyte cells.

Sulfides solid electrolytes have been extensively investigated due to their mechanical softness and high ionic conductivity. However, the electrochemical oxidation stability of those materials are as low as 2 V (vs. Na+/Na)[3]. Alternatively, the excellent ion conductivities and stability at high potentials have made halide compounds, intriguing candidates for solid electrolytes in batteries. These compounds offer fast ion transport, good stability at highly oxidative potentials, and are easily processed. A wide range of chemistries, such as A3MX6 (A = Li, Na; M = Sc, In, Y, Yb, Er, Hf, Ho, Dy, Al, Zr; X = F, Cl, Br, I), have been synthesized with tunable properties and the characterizations of those materials shows relevant electrochemical proprieties [2].

In our work, we investigate different Na-based chloride compounds by Density Functional Theory (DFT). We expand beyond the reported compositions to consider possible cation-substituted compounds. Here, we report on the structures, ionic conduction pathways and ionic conductivity (computed by molecular dynamics methods) expected for such compounds. In the next months, we will also evaluate the compounds´ chemical and electrochemical stability. Our work moves us one step closer towards the development of stable and highly conductive solid electrolytes for Na-based solid-state batteries.

References :

[1] J. Mater. Chem. A, 2021,9, 281-292

[2]J. Mater. Chem. A, 2022,10, 21565-21578

[3] ACS Energy Lett. 2022, 7, 10, 3293–3301
Designing Better Li Metal Anodes for Solid-State Batteries Using a Combined Experiment/Theory Approach
Authors: Wood Marissa , Xiao Yiran , Freyman Megan C. , Wang Bo , Zhu Cheng , Li Sichi
Published: February 2024

Solid-state batteries have the potential to transform energy storage by providing significantly higher energy densities and improved safety compared to conventional Li-ion batteries. Robust high-capacity Li metal anodes are necessary to realize this technology, but current Li metal anode designs suffer from significant degradation over time due to non-uniform Li plating/stripping and loss of contact with the solid electrolyte during cycling. Carbon scaffold hosts have been shown to mitigate this problem in liquid electrolyte systems by creating a uniform electric field and providing abundant Li nucleation sites, but they have not been well explored in solid-state systems, which require the fabrication of more complicated mixed ion/electron conducting scaffolds to provide transport of both Li ions and electrons throughout the anode. We investigated the effect of scaffold architecture and chemistry on the resulting Li morphology and electrochemical performance using a combined experiment/theory approach. Carbon scaffolds with well-controlled geometries and varied porosities were fabricated using 3D printing and then characterized by SEM, Raman, and XPS before cycling in cells to evaluate their performance as hosts for uniform Li plating/stripping. Atomistic and mesoscale modeling were used to predict how scaffold chemistry and microstructure affect Li nucleation probability and the formation of current density/stress hotspots that can lead to dendrite growth, and these results were used to help guide scaffold design. This work provides further insight into the relationship between anode architecture and Li metal cycling stability in solid-state batteries and demonstrates progress toward an anode-free configuration, which promises to simplify cell manufacturing, decrease cost, and increase energy density by plating the Li metal anode directly from the cathode in situ.

Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344.
In-Operando Spectroscopy to Study the Effect of Alkaloids on Polysulfide Shuttling in Lithium-Sulfur Batteries
Authors: Yim Taber , Pereira Rhyz , Kalra Vibha
Published: February 2024

Lithium-sulfur batteries are a promising next generation battery chemistry, but they are still hindered by the critical challenge of polysulfide shuttling. To address this problem, we investigated the novel application of alkaloids in lithium-sulfur batteries via in-operando IR spectroscopy. We did this by assembling an airtight electrochemical cell on top of an ATR-IR puck. To demonstrate the feasibility of the alkaloid material, we incorporated it into a sulfur cathode and studied the IR spectra in real time during battery cycling. We monitored the carbonyl peaks and found a reversible shift (strengthening/weakening) consistent with the appearance of polysulfides in the S-S region. This phenomenon corresponded directly with the 2.3V peak of the CV. This suggests a rapid polysulfide binding effect, as the polysulfides evolve, via polar-polar interactions between the oxygen of the carbonyl groups and lithium of the polysulfides. We believe the shift is particularly significant due to the presence of multiple carbonyl groups per molecule. This result is supported by shuttle current tests where we observed a lower concentration of polysulfides in the electrolyte for cells with the alkaloid material. We also incorporated this material into a conventional carbon-sulfur slurry cathode and saw an increase in both capacity and capacity retention. Finally, alkaloids can be derived from natural materials and represent a greener approach to the realization of the lithium-sulfur chemistry.
Porous Carbon Textile Decorated with VC/V2O3-X Hybrid Nanoparticles: Dual-Functional Host for Flexible Li-S Full Batteries
Authors: Nguyen Viet Phuong , Shim Hyungcheoul , Kim Jae-Hyun , Lee Seung-Mo
Published: February 2024

The polysulfide shuttling at the cathode and lithium dendrite formation at the anode remain as major obstacles to overcome for the realization of high-performance lithium-sulfur (Li-S) batteries. Here, via a facile one-pot synthesis using carbothermic reduction, we prepared a porous and flexible carbon textile uniformly decorated with VC/V2O3-x hybrid nanoparticles, which was used as a robust and flexible host material for both sulfur cathode and Li metal anode. We observed that the defective V2O3-x part traps polysulfides and the conductive VC part catalytically enhances the fragmentation of the polysulfides. Moreover, it was found that the well-distributed VC/V2O3-x nanoparticles act as lithiophilic sites to lead uniform lithium nucleation for a dendrite-free lithium metal anode. The full battery delivered superb rate performance (882 mAh g − 1 at 5 C) and an ultralow decay rate of 0.02% per cycle during 1000 cycles at 1 C. Even with a large sulfur loading of 7.0 mg cm−2, a high areal capacity of 6.29 mAh cm−2 at 0.2 C was obtained. This work provides an effective remedy to simultaneously resolve problems regarding the shuttle effect and the Li dendrite formation for the realization of high-performance flexible Li-S full batteries.
Multi-Scale Analysis of Lithium-Sulfur Pouch Cells Using Imaging Methods
Authors: Arlt Tobias , Schmidt Florian , Ziesche Ralf F. , Selve Sören , Boenke Tom , Abendroth Thomas , Lu Yan , Dörfler Susanne , Risse Sebastian , Althues Holger , Kaskel Stefan , Manke Ingo
Published: February 2024

Lithium-sulfur batteries (Li-S) are promising energy storage technologies. Its high gravimetric energy density, the abundance of sulfur and low costs at high production volume, this battery type is especially applicable for automotive and aerospace applications. In recent years, the number of reported prototype cells has increased, as well as their accessible energy density. This underlines the progress of technology readiness of the Li-S system. However, despite this important breakthrough density and cycling stability have to be overcome in the Li-S research. Additionally, the influence of the cathode porosity as well as the surface of the carbon material and the electrolyte composition play an important role on the conversion of sulfur and the performance of prototype cells.

Hard X-ray beamlines, as BAMline at the electron storage ring BESSY II in Berlin, Germany, have now been in service for over two decades. Several improvements have been implemented, allowing for operando tomography and fast radiographic measurements on the micrometer scale by using well-shaped synchrotron X-ray beam. In this study, operando X-ray imaging measurements on Li-S pouch cells are complemented by scanning and transmission electron microscopy and focused-ion-beam measurements on the nanometer scale delivering unique and multi-scale results about the morphology of sulfur inside the porous cathode material. Therefore, tiny pouch cells designs have been developed, allowing for operando tomography of stacked cells.

Figure 1
New Gel-Polymer Electrolyte for High-Performance Li‖LiFePO4 Cells with Enhanced Safety
Authors: Li Qi , Wang Jian , Wan Mintao , Passerini Stefano , Bresser Dominic
Published: February 2024

The use of lithium-metal anodes promises batteries with substantially higher energy densities due to their high theoretical capacity of 3860 mAh g-1 and low redox plateau of -3.04 V vs. the standard hydrogen electrode [1, 2]. Of particular interest in this regard is the combination with (quasi-)solid electrolytes, potentially enabling a stabilized interface with the lithium electrode compared to solely liquid electrolyte systems [3].

Herein, a new gel-polymer electrolyte based on a non-toxic, nitrogen-containing polymer is reported that provides flame-retarding properties and decreases the volatility of the liquid electrolyte phase, thus, reducing the flammability of the electrolyte system as a whole [4, 5]. In addition, this electrolyte enables very stable cycling of symmetric Li‖Li cells and superior cell performance in Li‖LiFePO4 compared to the liquid analogue. In fact, the commercial availability of this polymer renders a potential use in future rather straightforward.

References

[1] X. Dong, A. Mayer, X. Liu, S. Passerini, D. Bresser, ACS Energy Letters, 8 (2023) 1114-1121.

[2] H.P. Liang, M. Zarrabeitia, Z. Chen, S. Jovanovic, S. Merz, J. Granwehr, S. Passerini, D. Bresser, Advanced Energy Materials, 12 (2022) 2200013-2200024.

[3] K. Sashmitha, M.U. Rani, Polymer Bulletin, 80 (2022) 89-135.

[4] K. Kiran Kumar, M. Ravi, Y. Pavani, S. Bhavani, A.K. Sharma, V.V.R. Narasimha Rao, Physica B: Condensed Matter, 406 (2011) 1706-1712.

[5] J. Zieba, Y. Zhang, P. N. Prasada, Sol-Gel Optics 11, 1758 (1992) 403-409.
Probing the Mo-Redox in Alluaudite Battery Materials
Authors: Barman Pubali , Jha Pawan Kumar Kumar , Gopalakrishnan Sai Gautam , Canepa Pieremanuele , Barpanda Prabeer
Published: February 2024

Alluaudites are essentially naturally occurring mixed metal (Mn and Fe) phosphate-based minerals [1] consisting of an open framework structure to support fast alkali migration. The general formula for alluaudite can be expressed by A(1)A(2)M(1)M(2)2(XO4)3 where A and M sites are alkali ion and transition metals respectively and X can be S, P, As, Mo, W, V and so on [2]. The presence of polyanionic moieties (XO4) assures structural stability and high-voltage operation arising from the inductive effect [3]. Till date, a variety of phosphate and sulfate-based alluaudites have been reported as cathodes for Li-ion and Na-ion batteries [4,5].

In 2017, the first molybdate-based alluaudite material, Na2.67Mn1.67(MoO4)3, was reported as a 3.45 V Mn-based cathode [6]. Inspired by this work, we have explored other 3d (Co, Ni) based molybdate alluaudite homologues as potential compounds with desirable electrochemical and electrocatalytic activities.

Solution combustion synthesis was employed to prepare phase pure Na36Co1.32(MoO4)3 by restricting the annealing duration to one minute as compared to the reported solid-state route warranting prolonged (100 h) annealing. It was found to act as a high-voltage cathode (4 V vs Na/Na+ and 4.1 V vs Li/Li+) involving Co3+/Co2+ redox center [7] while cycling between 3.0 V to 4.3 V.

The above-mentioned alluaudite consists of Mo species, which can be redox-active at lower voltages. When cycled in a low-voltage window (0.01 V to 3.0 V), this material was found to act as an anode for both Li-ion and Na-ion batteries. High capacity (ca 400-500 mAh/g) was obtained with a central potential ~0.6 V involving conversion and (de)insertion reaction mechanism.

The Ni-analogue, Na4Ni0.8(MoO4)2 alluaudite, was studied as an anode material in both Li-ion and Na-ion batteries involving conversion and (de)intercalation redox mechanisms like the Co- analogue. The underlying redox mechanism will be described for both cases involving post-mortem diffraction, electron microscopy, and spectroscopic tools as well as with the help of the density functional theory (DFT) approach.

Finally, alluaudite Na4Cu(MoO4)3 was prepared by soft chemistry route, which was found to work as an anode material in the voltage window of 0.01 V to 3.0 V. The phase transformation and underlying redox mechanism will be elucidated.

References:

[1] D. J. Fisher, Am. Mineral. 40 (1955) 1100-1109.

[2] D. Dwibedi, P. Barpanda, A. Yamada, Small Methods 4 (2020) 2000051.

[3] P. Barpanda, L. Lander, S. Nishimura, A. Yamada, Adv. Energy Mater. 8 (2018) 1703055.

[4] P. Barpanda, G. Oyama, S. Nishimura, S.-C. Chung, A. Yamada, Nat. Commun. 5 (2014) 4358.

[5] D. Dwibedi, R. Araujo, S. Chakraborty et al, R. Ahuja, P. Barpanda, J. Mater. Chem. A 3 (2015) 18564-18571.

[6] J. Gao, P. Zhao, K. Feng, Chem. Mater. 29 (2017) 940-944.

[7] P. Barman, P.K. Jha, A. Chaupatnaik et al, P. Barpanda, Mater. Today Chem. 27 (2023) 101316.
Mechanistic Underpinnings of Heterogeneities in Solid-State Battery Cathode
Authors: Naik Kaustubh Girish , Vishnugopi Bairav Sabarish , Mukherjee Partha P.
Published: February 2024

Solid-state batteries (SSBs) are regarded as the potential candidate for next-generation energy storage systems due to their enhanced energy density and safety characteristics. However, realizing the true potential of the SSBs is predicated on addressing several interfacial and mechanistic challenges stemming from the mechanically rigid nature of the solid electrolyte (SE). In this regard, the presence of solid-solid point contacts within the solid-state cathode poses a critical bottleneck. Point contacts not only result in transport and kinetic limitations but also lead to stress hotspots within the composite cathode. Moreover, microstructural heterogeneities govern the spatial variability of these point contacts, thereby influencing the coupled electrochemical, thermal, and mechanical signatures. Thus, understanding the critical role of cathode microstructural heterogeneity in dictating the mesoscale interactions and its implications on the SSB performance is necessary. In this work, mechanistic underpinnings of heterogeneities in solid-state cathode will be studied and its implications on the coupled electrochemical-thermal-mechanical response of SSBs will be delineated. Lastly, the effect of cathode architecture will be explored towards achieving high energy density SSBs.
Digital-Twin Modeling and Simulations on All-Solid-State Batteries
Authors: Lee Yong Min
Published: February 2024

The use of digital twin technology for investigating all-solid-state batteries (ASSBs) has gained significant attention. Digital twin modeling is crucial in obtaining key design parameters such as effective ionic or electronic conductivity, specific contact area, which are difficult to obtain through experiments. This work presents two methods, bottom-up and top-down, for creating 3D microstructures of composite electrodes and discusses recent progress in upgrading both methods to uncover veiled parameters in ASSBs. Furthermore, the digital-twin electrode structures are coupled with electrochemical, thermal, and mechanical changes. This work is a valuable guideline for researchers working on ASSBs and related fields.

References:

1. Energy Storage Materials, 19 (2019) 124-129

2. Nano Energy, 62 (2019) 810-817

3. Chemical Engineering Journal, 391 (2020) 1235282

4. Advanced Energy Materials, 10(35) (2020) 2001563

5. ACS Energy Letters, 5(9) (2020) 2995-3004

6. Nano Energy, 79 (2021) 105456

7. Energy Storage Materials, 41 (2021) 289-296

8. Advanced Energy Materials, 12 (2022) 2103108

9. Energy Storage Materials, 49 (2022) 481-492

10. Nano Energy, 102 (2022) 107679
(Invited) Multiscale Modeling of Heterogeneous Interfaces for Hydrogen Production
Authors: Pham Anh Tuan
Published: February 2024

Improving performance of hydrogen production devices requires a detailed understanding of physicochemical processes at solid-gas and solid-liquid interfaces. However, probing behavior of these interfaces under working conditions remain a significant challenge for both simulations and experimental techniques. In this talk, I will provide an overview of our strategy for simulating heterogeneous interfaces within the HydroGEN Advanced Water Splitting Materials Consortium, ranging from first-principles calculations of chemical reactivity to machine learning approaches for accelerating theory-experiment integration and continuum methods for understanding microstructure effects. In particular, I will discuss how computational models can be used to elucidate mechanisms of interface chemical reactions and mass transport, as well as the formation of new phases and their impacts on materials stability and performance. I will also show how simulations have been integrated with experimental probes, such as X-ray spectroscopy, to obtain new understanding of materials interfaces under operating conditions. Finally, I will discuss how this understanding is being used to guide new strategies for improving materials functionality for hydrogen production.

This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
(Invited) Water Splitting Materials for Solar Thermochemical Hydrogen Production
Authors: Bishop Sean R , Smith Andrew I , King Keith R , Clauser Arielle L , Sugar Josh D , Ambrosini Andrea , Sanders Michael , Coker Eric N , McDaniel Anthony H
Published: February 2024

Solar thermochemical hydrogen (STCH) production uses concentrated sunlight to produce hydrogen using reduction/oxidation of metal oxides. Typically, the metal oxide is heated to high temperature (>1400 oC) causing it to release oxygen, then it is cooled to a lower temperature (<1000 oC) in steam whereby it re-oxidizes, stripping oxygen from water molecules and producing hydrogen. Due to improved stability, non-stoichiometric oxides that do not change phase during the STCH process are typically used, even though the reversible oxygen content is less than phase changing materials. HydroGEN (h2awsm.org) is an Energy Materials Network supported by the U.S. Department of Energy’s Hydrogen and Fuel Cell Technologies Office, and is focused on the development of new water splitting materials for STCH by fostering collaboration between U.S. national laboratories and external entities such as academia and industry. In this presentation, recent progress in developing new water splitting materials led by Sandia National Laboratories (SNL) will be presented. STCH performance of select materials predicted from a defect Graph Neural Network trained on crystal structures derived from density functional theory, subsequently synthesized and characterized using thermogravimetric analysis and flow reactor measurements, will be presented. Additionally, there will be discussion of benchmarking metrics and characterization of exemplar STCH materials. Lastly, trends in water splitting materials and durability considerations and challenges for commercialization will be discussed.

SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
(Invited) Hydrogen Benchmarking Project: Progress and Future Opportunities
Authors: Ayers Katherine E. , Carmo Marcelo , Roberts George , Marina Olga A , Stechel Ellen B , Xiang Chengxiang("CX") , Gross Karl
Published: February 2024

The DOE Benchmarking project was created to foster consistency in testing and standards for advanced water splitting technologies, including high and low temperature electrolysis, solar thermochemical pathways, and photoelectrochemical water splitting. The goal was also to bring the water splitting community together in order to learn from each other and leverage synergies in methodology, knowledge, and tools across different technologies.

Over the first phase of the project, accomplishments have included establishing a regular series of workshops, discussing priority areas for each technology as well as cross-cutting areas. The outcomes of these workshops have included a set of frameworks defining tests which would be useful to standardize across the field, priority research directions and relative risk level/time to develop, and a first set of protocols focused on material development.

Next steps include refreshing the priority areas outlined 4 years ago, continuing to develop standardized protocols with a higher focus on component and device level especially for the more mature technologies, validating the existing protocols, and continuing to engage the community including international researchers. Validation includes ensuring that the protocol can reproducibly achieve consistent results for standard materials, and could involve setting up qualified labs for testing novel materials. The workshops will continue to be an essential part of advancing the benchmarking, protocols, and roadmaps, through providing a community forum to discuss research needs, share best practices, and maintain cohesive direction.

This talk will describe the success of the program to date, and plans for the next phase of the program.
(Invited) The Need for Standardized Benchmarking of Solid Oxide Cells
Authors: Lenser Christian , Menzler Norbert H.
Published: February 2024

Solid Oxide Cells (SOC) have been the subject of intense scientific research in the past few decades, and significant progress has been achieved to increase the power output. While promising efforts to further industrialize the technology are underway, an increase in the performance of SOCs is still the scope of many scientific publications. However, progress in cell performance is increasingly hard to gauge due to a lack of comprehensive testing standards. Furthermore, many researchers publish performance data without providing all the necessary information about the testing conditions, or use metrics that do not allow comparison to other works.

In particular, the “peak power density” (PPD) is often used to characterize cell performance. The PPD is unsuitable as a performance indicator since it is far removed from a relevant working point for an SOFC, and depends to a large extend on the experimental conditions. To make matters worse, the PPD of high-performance cells is located at very high current densities, exacerbating the influence of the experimental conditions (which are often not described in detail or at all) and experimental artifacts on the measured performance. As a result, claims of increased cell performance may not hold up when applying standardized testing criteria.

This contribution summarizes the most important aspects that are relevant for performance evaluation of SOCs, focusing on those with the highest impact on apparent cell performance. Furthermore, the limitations of performance indicators on the cell level will be illustrated by comparing them to stack-level performance, and additional losses incurred under application-oriented operation conditions will be discussed. Since cell testing is often the key test to assess performance of novel materials and processing routes, comparability of the results is critical to scientific progress and therefore relevant for the community as a whole.
(Invited) Local pH in the (Photo/Electro) Catalytic Environment
Authors: Houle Frances
Published: February 2024

(Photo)electrodes designed for improved efficiency and selectivity for CO2 reduction are often nanostructured, for example highly roughened metal films, nanowire arrays, and catalyst particles within a gas diffusion electrode. In all cases, local pockets of water with dissolved CO2 and ions are necessary for the reduction reaction. Although these regions are thought of as having a pH, they are often too small to have a well-defined pH or be at thermodynamic equilibrium until a minimum electrolyte pool size is reached. Computational studies using stochastic chemical kinetics provide a window into this environment, bridging the nanometer scale to the bulk-like scale. The calculations show that the compositions of these regions are characterized by large concentration fluctuations including periods of time when some ions are not present at all. The calculations enable useful trends in electrolyte composition to be identified as a function of electrolyte pool size, providing insights to the complex environments surrounding the catalytic center.
Forward-Bias 3D-Junction Bipolar Membranes for Electrochemical CO2 Reduction to CO
Authors: Kwen Jiyun , Herranz Juan , Schmidt Thomas J.
Published: February 2024

The ongoing, rapid increase in atmospheric CO2 concentration has led to a growing interest in the electrochemical reduction of CO2 to value-added products like CO. To attain high current densities, the latter reaction is often performed using an anion exchange membrane(AEM) electrolyte that is well known to operate through the transport of (bi)carbonate ions from cathode to anode. This can in turn result in a CO2 pumping effect that decreases the device’s net CO2-consumption, and that can be prevented by using a bipolar membrane in a so-called forward-bias configuration (i.e., with the anion vs. cation exchange layers (AEL, CEL) contacting the cathode vs. anode electrodes, respectively). However, the recombination of protons and (bi)carbonate and concomitant production of H2O and CO2 at the AEL-CEL interface in this operative mode can also lead to the delamination of the membrane and cell failure.

In order to prevent such a delamination, this study proposes the introduction of a three-dimensional (3D) AEL-CEL junction, utilizing Nafion® as the cation exchange layer and PiperION as the anion exchange one. Two different methods were applied to fabricate the 3D junction bipolar membrane. The first method involves the fabrication of a 3D interlocking layer using polystyrene (PS) beads that are sprayed (along with Nafion ionomer) onto a Nafion membrane, and removed using toluene. This results in an inverse-opal structure atop the Nafion membrane whose pores can be filled with anion exchange ionomer (AEI). Complementarily, the second method involves the introduction of a layer, consisting of a mixture of AEI and cation exchange ionomer (CEI) between the AEM and CEM. Additionally, a non-conductive oxide material is added to this ionomer layer to increase the contact area of AEI and CEI. Finally, the electrochemical CO2 reduction performance and durability of the resulting, 3D junction bipolar membranes are evaluated and compared to those of an equivalent, 2D junction bipolar membrane, in all cases in a forward bias configuration.
Selective Ion Conducting Polymers for Non-Aqueous Redox Flow Battery Applications
Authors: Geise Geoffrey M.
Published: February 2024

Providing sustainable supplies of clean energy is a critical global challenge for the future. As intermittent renewable energy sources are increasingly deployed, grid-scale energy storage solutions are increasingly needed. One approach to addressing this challenge is to use flow battery technology to store and deliver grid-scale amounts of energy. Non-aqueous redox flow batteries can be operated at higher voltages and energy densities compared to aqueous systems and, as such, may offer high volumetric energy density compared to other flow batteries. A significant challenge facing non-aqueous flow batteries, however, is the lack of selective membrane separators engineered for the unique challenges of non-aqueous electrochemical systems. Suitable membranes for non-aqueous redox flow battery applications must be stable in aggressive solvent environments, offer high conductivity, and provide selectivity to prevent cross-over of redox active molecules. Here, we report the synthesis and characterization of a series of negatively charged ion conductive polymeric membranes for non-aqueous flow battery applications. Fixed negative charges were added to a poly(phenylene oxide) backbone via a custom sulfonate group-based side chain. Lithium ion conductivity and ferrocene permeability properties were characterized to evaluate the selectivity of the membrane for ion transport relative to redox active molecule cross-over (as ferrocene is a representative redox active molecule). The polymers exhibited combinations of conductivity and selectivity that are favorable compared to other Nafion-based materials, and the materials appear to be dimensionally stable in a non-aqueous electrolyte over a period of several months. Redox active molecule cross-over was analyzed within a thermodynamic regular solution framework to highlight how thermodynamic factors contribute to cross-over properties. Ultimately, the data suggest a decoupling of ion and redox active molecule transport that could inform future efforts to develop advanced non-aqueous redox flow battery membrane separators. Altogether, this presentation discusses the transport properties and stability of these materials that show promise for non-aqueous flow battery applications.
(Invited) Materials Challenges for the Green Hydrogen Economy at Scale
Authors: Swider-Lyons Karen , Mittelsteadt Cortney
Published: February 2024

Research and development projects over the last 30 years have successfully shown the value of hydrogen as a fuel and energy storage medium, and now hydrogen is seen as a key solution to decarbonization. Green hydrogen can be made by electrolysis anywhere that there is ample hydroelectric, solar and wind electric power. The hydrogen energy can be converted back to useful work in a fuel cell, turbine, or engine, or directly to manufacture products such as ammonia, cement, and steel. However, world decarbonization at scale also requires the demonstration of hydrogen at scale, and the widescale adoption of hydrogen for a green economy requires a reimagining of how energy is created, stored and used.

Leading technologies for the green hydrogen economy include proton exchange membrane fuel cells (PEMFCs) and PEM water electrolyzers (PEMWE), both which operate under acidic conditions. In addition to high electrocatalytic activity, the electrode materials must be designed for two- phase flow of water and gas. All of the materials should be durable, low cost, manufacturable, recyclable, and have the appropriate electronic and thermal properties.

This talk will describe some of the materials challenges needed to meet commercialization goals for PEMFCs and PEMWEs, and some of the constraints of manufacturing and recycling.
(Digital Presentation) Study of Structural and Ionic Conductivity Property in Gd3+ and Sm3+ Co-Doped Ceria for Low Temperature SOFC Electrolyte Application
Authors: Vinchhi Prerna , Vinchhi Prerna
Published: February 2024

In recent years, fuel cells have become one of the most efficient and clean energy conversion devices. Due to their use in stationary as well as mobile power applications, they have also gained a lot of attention in this field. From all other fuel cells, SOFC has several advantages such as absence of liquid component, vibration free working, fuel and many more. However, two most crucial aspects of SOFC are operating temperature and the choice of electrolyte materials. It is the most efficient fuel cell with a setback in its elevated operating temperature, as high as around 800℃ -1000℃. To achieve high ionic conductivity in a SOFC, it is very important to tailor the electrolyte properties, simultaneously reducing the operating temperature.

Conventionally, Yttria Stabilized Zirconia (YSZ) has been the most studied electrolyte material with a limiting factor of its high operating temperature. Doped Ceria has been one of the most explored alternatives of YSZ, which not only reduces the operating temperature but also enhances the ionic efficiency due to its electro-catalytic property. The double valency property of CeO2 occurring due to oxygen non-stoichiometry (CeO2-δ), generates oxygen vacancies making it a potential electrolyte material. Rare Earth (RE) dopants like Gd3+ and Sm3+ have reported to have high ionic conductivity at low temperatures. In the present study, synthesis of Sm-Gd- co-doped CeO2 by wet chemical route to ensure homogenous distribution, with the stoichiometry Ce1-a Gda-y Smy O2-0.5δ where a=0.20 and 0≤y≤a. It was prepared by modified co-precipitation method wherein, no additional water has been utilized during the co-precipitation process in order to minimize the particle agglomeration. Phase pure particles were obtained by calcining the precipitants at 650℃ in air and the green body made from it were sintered in air at elevated temperature of 1450 °C to achieve high density pellet. XRD and Raman spectroscopy confirmed successful substitution of both dopants and presence of single-phase cubic structure of the nanoparticles. The surface morphology was studied using FESEM which showed highly dense structure with more than 97% density. The electrochemical impedance spectroscopy (EIS) of the sintered pellets in the temperature range of 400-700℃, showed much higher conductivity then singly doped Ceria .

Figure 1
(Digital Presentation) Efficient Mixed Ionic Electronic Conductor (MIECs) for Conventional SOFC
Authors: Raza Dr Rizwan , Rasool Shahzad
Published: February 2024

A new kind of composite material has been developed to use for electrochemical conversion in solid oxide fuel cells (SOFCs) and semi-ionic fuel cells (SIFCs). The developed composite material based on Ni0.1Cu0.1Ce0.8, NiCuCeO with different ratios exhibited the exceptional properties of MIECs. Here the material 8NC2C employed in SOFC showed good electronic, ionic conductivity and total conductivity 1.480, 0.098 and 1.578 S/cm respectively. However, by comparison material composition 8NC2C rendered the open circuit voltage (OCV) 1.097 V and fuel cell performance 765.099mW/cm2at 550°C for SOFC and reasonably good value of good fuel cell performance of 678.659 mW/cm2 at 550°C was observed by SIFC 4NC6C composition. The comparative study showed that total conductivity, fuel cell performance and polarization resistance of SOFC exhibited better results than SIFC nevertheless 4NC6C composition polarization resistance Rp was lower in SIFC over SOFC which establish the SIFC as a good candidate for fuel cell application.
Core-Shell Nanofiber Composites As Highly Active and Robust Anodes for Direct-Hydrocarbon Fueled Solid Oxide Fuel Cells
Authors: Choi Yoonseok , Cho Hee-jin , Kim Jinwook , Kang Joon-Young , Seo Jongsu , Kim Jun Hyuk , Jeong Seung Jin , Lim Dae-Kwang , Kim Il-Doo , Jung WooChul
Published: February 2024

Direct use of methane in solid oxide fuel cells (SOFCs) can be a key to realize the high-efficiency advantage of fuel cell technologies before mature hydrogen economy. One of the most critical issues for direct-methane SOFCs is to prevent anode, particularly Ni-based, from carbon deposition (coking) that drastically degrades performance. A number of ceramic anodes have been developed to exhibit excellent coking resistance but their application is still limited by relatively low electrochemical activity. Impregnating catalytically active and high oxygen ion-conducting materials such as doped ceria to form nanoscale composites, some ceramic anodes demonstrated enhanced activity comparable to Ni-based anodes. However, fabrication methods employed so far require repetitive series of a coating and high-temperature calcination step to optimize the performance, which detrimentally affects nanoarchitectures. To address this issue, we demonstrate electrospinning as efficient route to prepare nanocomposite ceramic anodes. We successfully achieve highly active and robust anodes based on core-shell-like La0.75Sr0.25Cr0.5Mn0.5O3@Sm0.2Ce0.8O1.9 nanofibers through co-electrospinning method. Such nanoscale morphologies are maintained by the durable ceria shells at elevated temperature. Compared to the traditionally mixed counterpart, it shows nearly a half polarization resistance due to the increased active reaction sites and high stability in a wet methane at 700℃ for about 100 h.
Thin Membranes Using PFSA-Vinylon Intermediate Layer for PEM Fuel Cells
Authors: Kim Jedeok , Yamasaki Kazuya , Ishimoto Hitoshi
Published: February 2024

Fuel cells are attracting attention as one of the key energy devices for achieving carbon neutrality in 2050. Currently, fuel cells are being improved for versatile mobile applications. Among the components of fuel cell devices, polymer electrolyte membranes for proton exchange, in particular, are required to have high proton conductivity at high temperature, high and low humidification, and thin membranes. Proton-exchange fuel cells utilize perfluorosulfonic acid (PFSA) ionomers and membranes from Chemours and 3M and Solvay [1]. Nafion membranes with a thickness of 178-25 μm and Gore select membranes (with reinforcement) with a thickness of 20-5 μm have been commercialized [2,3]. On the other hand, thinner polymer electrolyte membranes can reduce the ohmic voltage drop in fuel cells to improve performance and lower costs. However, it is difficult to obtain thin membranes of less than 20 μm without reinforcement using PFSA ionomers.

In this report, a thin PFSA electrolyte membrane (10 μm) without reinforcement was successfully developed by introducing a PFSA-vinilon composite layer as an intermediate layer of the PFSA membrane. The fuel cell evaluation revealed that it has a high current density.

The ionomers used were 5% Nafion solution (DE520 CS type, EW=1100) and 6% Aquivion solution (D83-06A, EW=830). PVA (polyvinyl alcohol) was synthesized from polyvinyl acetate (PVAc, Mw=100,000). The laminated membranes (10 μm thickness) was obtained by preparing a 2 μm PFSA layer, followed by a 6 μm PFSA-PVA composite layer, then a 2 μm PFSA layer was coated. Finally, laminated membranes with PFSA-Vinylon composite layers were obtained by Formalization reaction the PFSA-PVA composite layers.

FTIR evaluation of the PFSA/ PFSA-Viynylon/ PFSA multilayers confirmed the presence of an intermediate layer by observing Vinylon-derived peaks. Conductivities of about 4.5 mS/cm and 2.5 mS/cm in the thickness direction were obtained at 80°C, 90%RH and 20%RH, respectively. On the other hand, I-V evaluation was performed at 80°C, 100%RH and 35%RH using hydrogen, oxygen and air. Nafion 212 was used as a comparison membrane. The I-V characteristics of the laminated membranes showed higher current density than that of the Nafion membrane. Maximum current densities of 3 A/cm2 at 0.6 V and 3 A/cm2 at 0.4 V were obtained at 80°C, 100% RH and 35% RH with hydrogen and oxygen, respectively. Regarding the comparison of PFSA ionomers, Aquivion showed higher performance at higher current densities than Nafion [4].

References

[1] A. Kusoglu, A.Z. Weber, Chem. Rev.
2017, 117, 987–1104.

[2] J.A. Kolde, B. Bahar, M.S. Wilson, T.A. Zawodzinski, S. Gottesfeld, Electrochem. Soc. Proc.
1995, 95-23, 193–201.

[3] B. Kienitz, J.Kolde, S. Priester, C.Baczkowski, M. Crum, Electrochem. Soc. Trans.
2011, 41(1) 1521-1530.

[4] J. Kim, K. Yamazaki, H. Ishimoto, Y. Takata, Polymers, 2020, 12, 1730-1735.
Washable and Eco-Friendly PEDOT:PSS Coated Silk Yarn Based-Transpiration-Driven Electrokinetic Power Generator with Tremendous Energy Generation
Authors: Yoon Hyungsub , Hwang Byungil , Yun Tae Gwang
Published: February 2024

Since the importance of eco-friendly technologies and environmental consideration has been increased gradually, energy harvesting technologies that generate electricity from ambient has been gained attentions, including a solar cell, a piezoelectric, a triboelectric, and a thermoelectric device. However, since the relative low energy generation efficiency has been considered as the obstacle, the research on a novel energy harvesting technology is necessary.

A transpiration driven-electrokinetic power generator (TEPG), one of the hydro-electric nanogenerators, has been developed recently and researched due to the abundant energy resource (water), the ability to generate energy continuously, no sensitivity to ambient condition, etc. The basic concept is based on the transpiration process where the water flows from roots to leaves by water gradient in the plants. The water gradient in TEPG system is formed with dropping water at one side of the device. There are two main components, including a conductive material and a hydrophilic substrate. The conductive materials with high surface area capture the cations in solution to decrease a surface energy, leading to formation of the electrical double layer. The hydrophilic substrate promotes the flow of solution along the substrate, leading to the transfer of electrons in the conductive material.

Herein, we utilize the PEDOT:PSS as conductive material and silk yarn as hydrophilic material. A silk yarn is a natural and biodegradable material with the high mechanical properties, lightweight, and biocompatibility. PEDOT:PSS is promising candidate for TEPG device because its negative charged PSS groups attract the cations selectively via electrostatic interaction, leading to the increase of potential difference between wet/dry region. However, the low washing resistance of PEDOT:PSS is the limitation for practical wearable devices since the cleanness is essential. During the cleaning process, the PEDOT:PSS is easily detached from the substrate. Therefore, the research on the PEDOT:PSS with sufficient water resistance is essential for its wider utilization. In general, an ethylene glycol (EG) is commonly used for improving water resistance of PEDOT:PSS through hydrogen bonding with PSS parts. However, it is also known as the agent to enhance electrical conductivity via removal of excess PSS. Thus, we introduce the divinyl sulfone (DVS) as a covalently cross-linker for enhancing washing resistance of PEDOT:PSS. In this work, we compare the energy generation performance and washing resistance of various PEDOT:PSS coated TEPGs without and with EG or DVS, named as PS-TEPG, PES-TEPG, and PDS-TEPG, respectively.
Nickel-Doped Cobalt Oxyhydroxide Nanowires Coupled Polyaniline Functionalizedcarbon Cloths As Multifunctional Electrocatalysts for Hydrogen/Oxygen Evolutionreactions at All pH Levels
Authors: Lingappan Niranjanmurthi , Lee Wonoh
Published: February 2024

Hydrogen represents a carbon-free and sustainable energy carrier. Electrochemical water splitting via hydrogen

evolution reaction (HER) and oxygen evolution reaction (OER) is a green approach for the hydrogen production.

Nevertheless, unfavorable thermodynamics and sluggish kinetics limit the water splitting efficiency. While the

benchmark catalysts such as Pt@C and RuO2/C catalysts display remarkable catalytic activity, the inferior

durability remains a major concern. Further, scarcity and high demand result in sharp rise in cost, hindering their

large-scale commercialization. Herein we rationally design the synthesis of nickel-doped cobalt oxyhydroxide

nanowires grown on PANi functionalized CF (Ni@CoOOH@PANi-CF) as multi-functional electrocatalyst for HER

and OER. In this design, the interfacial PANi layers substantially improve the surface functionality of the CF

substrate and thereby facilitates strong coupling interaction with the Ni@CoOOH catalyst, which influences the

charge transport kinetics across the catalyst/substrate interface and also maintains the structural integrity of the

overall catalyst throughout the cyclic and long-term durability tests. Furthermore, the Ni@CoOOH provide

abundant active sites for the dissociation of water, while the PANi-CF facilitates the adsorption of H+ ions from

the intermediates and promotes its convention to hydrogen molecules, which accelerates the HER effectively.

Due to these intriguing features, the Ni@CoOOH@PANi-CF manifested remarkable HER efficiency with low

overpotential (35, 30, and 100 mV mV at 10 mA cm-2) in acidic, alkaline, and neutral electrolytes. Besides, the

Ni@CoOOH@PANi-CF demonstrated batter durability even in acidic electrolyte. As a key functionality, PANi

layers protected the carbon surface from corrosive reactions and suppressed the active catalyst dissolution,

resulting in high tolerance for both HER and OER at all pH conditions.
Exploring the Activity-Stability Landscape of Nife-LDH for the Oxygen Evolution Reaction at Industrially Relevant Alkaline Electrolysis Conditions
Authors: Iqbal Sarmad , Müller David , Chatzichristodoulou Christodoulos
Published: February 2024

Developing an efficient and robust electrocatalyst for the oxygen evolution reaction (OER) that is free from scarce raw materials is of paramount importance for the sustainable production of green chemicals and fuels. Significant efforts have been devoted to improving OER activity, while the robustness of OER electrocatalysts has been less dwelled upon.1 Even for NiFe-LDH, which is known to be one of the most active transition metal-based OER electrocatalyst in alkaline media, its long-term stability under industrially relevant conditions remains questionable, partly because of the many parameters that can influence it. The stability of NiFe-LDH is known to depend on operating conditions (overpotential, current density, temperature of electrolyte, etc.), electrolyte composition (pH, type, and concentration of cations), and its structural and chemical characteristics (diameter and thickness, i.e. number of layers of platelets, intercalating anions, orientation, composition, point and extended defects, etc.). Recent studies have shown that the stability of NiFe-LDH can be improved by inducing cationic vacancies, exfoliation of nanosheets of NiFe-LDH, and by injecting Fe species in the electrolyte.2
,
3 Though these studies have shown improvement in the long-term stability of NiFe-LDH in mild operating conditions, the stability of NiFe-LDH is expected to aggravate sharply when tested at industrially relevant conditions (i.e., operating at high current density of 1 A cm-2 in 6 M KOH at 80 ℃). In this contribution we will report the activity and stability of NiFe-LDH for OER at industrially relevant conditions by employing long-term testing and operando Raman investigations. We expect this study to help guide the future design of advanced NiFe-LDH based electrocatalysts for OER.