bluuebunny/crossref_metadata_2025 huggingface dataset:
Conditional GAN for Generation of 3D SOFC Electrode Microstructure Dataset
Authors: Kishimoto Masashi , Matsui Yodai , Iwai Hiroshi
Published: September 2023

Synthetic three-dimensional porous structures of solid oxide fuel cell anode are generated using the deep convolutional conditional generative adversarial neural network (DCCGAN). The developed network consists of a generator that produces an artificial structure dataset from random numbers, so-called latent variables, and a discriminator that judges whether the input structure dataset is real or fake. The generator and discriminator are alternately trained to improve their performance in an adversarial manner so that the generator can eventually create realistic structures indistinguishable from the real ones. The training process is performed using the real structure dataset of conventional Ni-YSZ anodes with different solid volume ratios, i.e., Ni: YSZ = 70:30, 50:50, and 30:70. In this study, additional training is performed for the generator to control the volume fraction of the generated structures. First, the values of the volume fractions are input to the generator alongside the latent variables. Then, the volume fraction loss is calculated from the difference between the volume fractions of the generated structure and the input values. Finally, the volume fraction loss is used to train the generator in addition to the ordinal training process. The trained network is validated by comparing the generated structures with the real structures in terms of microstructural parameters such as volume fraction, surface area density, and triple-phase boundary density. This comparison is conducted not only for the structures used for the training but also those that are not used for the training, i.e., a solid volume ratio of Ni: YSZ = 40:60 and 60:40. It is found from the results that the volume fractions of the generated structures are in good agreement with the specified input values to the generator. Also, other microstructural parameters quantified from the artificial microstructures are similar to those of the real structures. In addition, since the developed network does not contain fully-connected layers, and is hence categorized as a fully-convoluted network, structures with arbitrary sizes can be generated using the same generator by changing the dimension of the latent variables. The generated structures are confirmed to be free from digital artifacts such as noise, disconnectivity, and periodicity in structures.
Investigation of the Abnormal I-V Curve Shape of Hybrid Direct Carbon Fuel Cell Using Lanthanum Strontium Calcium Titanate-Based Anode
Authors: Liu Xinyu , Irvine John T.S.
Published: September 2023

Solid oxide direct carbon fuel cell are being developed for use with waste derived materials. To avoid problems of the state-of-art Ni/YSZ anode, perovskite-based anode materials are being investigated. We have fabricated solid oxide fuel cells with La0.2Sr0.25Ca0.45MxTi1-xO3-
δ (M=Ni, Fe, or Co) anodes, YSZ electrolyte, and LSM cathode. Electrochemical performance of these cells have been evaluated with both hydrogen and solid carbon as the fuel and promising results have been recorded. For example, fuel cells with La0.2Sr0.25Ca0.45Ni0.05Ti0.95O3-
δ anode tested in hybrid direct carbon fuel cell mode reached a maxmium power density of 82.3 mW/cm2 measured in N2 purging gas at 850 °C. During hybrid direct carbon fuel cell testing with solid carbon fuel and nitrogen purging gas, I-V curves obtained showed an abnormal shape between 0.6V to 0.7 V. To investigate the origin of this line shape, we have used methods such as electrochemical impedance spectroscopy, potentiostatic study, analyzing of off gases from fuel cell using gas choromotography, SEM imaging, EDS analysis and Raman mapping of the tested fuel cell. These results can not only help explain the observed shape of I-V curve, but also provide insight into the mechanism of hybrid direct carbon fuel cells, thus benefiting further development of fuel cells for solid waste to energy applications.
Electrochemical Activation and NAP-XPS As Well As EIS Characterization of La0.31Sr0.58Ti0.97Ni0.03O3-δ Thin Film Electrode
Authors: Nurk Gunnar , Ainsar Mait , Kodu Margus , Kelp Glen , Romann Tavo , Lust Enn , Gallet Jean-Jacques , Kukk Edwin , Kooser Kuno , Möller Priit
Published: September 2023

Mixed conductive perovskites, like LaxSr0.9-xTiyNi1-yO3-d, LaxSr1-xCryMn1-yO3-d are attractive materials for SOFC anodes. These structures are flexible to adopt different cations into the structure. To improve catalytic activity of these materials, doping of perovskite B-site with metals like Ni, Co, Mo or Cu has been proposed. It has been demonstrated, that at elevated temperatures and in reducing atmosphere these dopants exsolve to perovskite surface to form nanometre scale catalyst particles [1,2]. Exsolution process could be accelerated by using electrochemical polarization. Other phenomena which has been observed in the case of these materials is the segregation of A-site elements because of elastic and electrostatic interactions of ions in the surface layer [3]. The extent of aforementioned effects is connected to the oxidation state of the B-site elements, which is a function of the chemical composition and the stoichiometry of the electrode material, the oxygen partial pressure in electrode compartment and temperature. To improve the understanding how the chemical composition of electrode surface depends on the electrode stoichiometry and environmental conditions it’s necessary to carry out in situ or operando characterization of electrode materials.

In the present study thin film electrodes with La0.31Sr0.58Ti0.97Ni0.03O3-δ composition was deposited using pulsed laser deposition (PLD) technique. Current collectors were made from Pt (using magnethron sputtering) and placed under the thin film electrode layer.

Electrodes were characterized usin XPS and EIS method at near ambient pressure conditions (1-5 mbar) at 650 °C, activated electrochemcally and characterized again to see the effect of activation. Changes on the electrochemical performance as well as on XPS data caused by electrochemical activation were observed and analyzed.

[1] Homel et al., J. Power Sources 195, 6367 (2010)

[2] Steiger, P., et al., Mater, 31, 748−758 (2019).

[3] Lee et al., J. Am. Chem. Soc. 135, 7909 (2013).
Utilizing Advanced Bipolar Membranes in Next Generation Electrodialysis Systems
Authors: Traenkle Olivia , Boettcher Shannon W.
Published: September 2023

Bipolar membrane electrodialysis (BPMED) is an essential process used in various industrial applications, such as water purification and acid/base production. Additionally, advanced BPMED systems are an integral component of larger CO2 sequestration technologies, allowing for ease of pH control within these systems. Improving these systems is vital to mitigating the global effects of climate change. To develop a viable advanced BPMED scheme, it is necessary to acquire bipolar membranes (BPMs) that operate at minimal voltage loss, high current density, and exhibit little ion crossover, while maintaining high performance over an industrially adequate timeframe. Researchers, such as Oener et al., have advanced BPM designs with the introduction of metal oxide catalysts to the interface of the cation- and anion-exchange layers of the BPM. These advanced BPM have shown a significant reduction in the energetic requirements of water dissociation. Applying these findings to BPMED has the potential to significantly improve the efficiency of BPMED systems, however, the BPM electrolyzer used for the development of these BPM are not directly analogous to an electrodialysis system. Thus, I present here a custom-built BPMED system that allows for the assessment of the specific voltage contributions of each component within the overall BPMED system. Using this tool, we aim to identify and address the performance and durability limitations of advanced BPM in BPMED by monitoring signs of degradation, such as blistering and delamination, and by monitoring changes in the potential drop across the BPM as conditions within the BPMED system are manipulated. This will lead to enhanced efficiencies and increased durability in BPMED applications, allowing for its integration into emerging CO2 sequestration systems, as well as other stacked membrane systems.
In Situ Construction of Metal/Ruddlesden-Popper Oxide Heterointerface for Promoting CO2 Electrolysis in Solid Oxide Electrolysis Cells
Authors: Choi Junil , Jang Daehee , Ha Jungseub , Kim Won Bae
Published: September 2023

Recently, solid oxide electrolysis cells (SOECs) have been suggested as an efficient CO2 conversion system with its fast electrode kinetics and high-energy efficiency. However, conventional Ni/YSZ cathode has been suffered from serious degradation problems, such as particle agglomeration and carbon deposition, etc. Herein, we designed the metal/oxide heterointerface on Ruddlesden-Popper (R.P.) oxide by in situ exsolution strategy.[1] The cathode catalyst, La1.2Sr0.8Mn0.4Fe0.6O4−
δ (R.P.LSMF) decorated with exsolved Fe nanoparticles (NPs), was prepared by simple in situ annealing of La0.6Sr0.4Mn0.2Fe0.8O3-
δ (LSMF) in H2 atmosphere and showed high current densities of 2.04, 1.43, and 0.884 A·cm−2 at 850, 800, and 750 °C, respectively. This superior electrolysis performance can be attributed to the in situ construction of Fe NPs anchored on R.P. oxide and to the increased contents of oxygen vacancies in R.P.LSMF. Furthermore, we also investigated the effect of dopant on the catalytic activity and the reduction stability of reduced LSMF. The Ni dopant on the B site can facilitate the formation of Ni-Fe alloy NPs during the exsolution process, while doping of Mo6+ species can enhance the phase stability of the R.P. oxide due to its high valence states.

[1] J. Choi et al., J. Mater. Chem. A, 2021,
9
, 8740-8748.
Utilizing a Transparent Conductive Encapsulant to Protect Photoelectrodes during Solar Fuel Formation
Authors: Rome Grace , Intia Fry , Klein Talysa , Schicht Zebulon , Tamboli Adele , Warren Emily L. , Greenaway Ann L
Published: September 2023

Carbon-neutral electricity is rapidly becoming available worldwide as solar and wind technologies advance, but storing energy in chemical bonds will remain a critical need for the transportation sector, as planes and other energy intensive processes will still require liquid fuels. Solar fuels, utilizing sunlight to directly convert CO2 into useful chemicals, are a renewable and net carbon-neutral way to produce needed liquid fuels. However, a common problem with photoelectrochemical solar fuel production is semiconductor degradation from submersion in aqueous environments. An ideal protective layer should 1) prevent solution from reaching the semiconductor, 2) maintain charge transfer to and from the solution, and 3) be transparent to light above the semiconductor band gap. While there presently are protective layer options that meet all three requirements, such as leaky TiO2 and MoS2, they are not easily adaptable to new semiconductor surfaces and/or to new electrochemical reactions. This can make protection difficult for newly developed photoabsorbers and catalytic reaction pairings. In this work, we demonstrate the use of transparent conductive encapsulants (TCEs) to meet these three requirements while also allowing for photoelectrode- and catalysis-agnostic adaptability. TCEs are composed of an ethyl vinyl acetate (EVA) matrix with embedded conductive metal-coated poly(methyl methacrylate) (PMMA) microspheres that can be attached to substrates through a lamination process. First, we characterize the electrochemical behavior of TCE-coated electrodes using the reduction of methyl viologen, demonstrating electrical conduction through the TCE layer. Results from a pinhole detection apparatus suggest the TCE is initially defect free and thus able to prevent solution from reaching the substrate. Then, we perform photoelectrochemical measurements of TCE-covered semiconductors to demonstrate the flexibility of this protection scheme for multiple materials. We also show the results of long-term photoelectrochemical measurements designed to probe the efficacy of TCEs as protective layers. These findings demonstrate that TCEs are an effective protective layer for a variety of photoelectrochemical applications.
Se-Doped Porous Carbon Supported Pt to Boost Selective Oxidation of Ethylene Glycol to Glycolic Acid
Authors: Jang Daehee , Maeng Junbeom , Kim Jihoon , Park Gwan Hyeon , Kim Won Bae
Published: September 2023

Biomass-derived polyols can be reformed to value-added chemicals by electrochemical selective oxidation process. Ethylene glycol (EG) and glycerol (GLY) are produced in a large surplus, hence rational design of electrocatalysts for efficient selective oxidation of these biomass-derived molecules should be required to utilize the EG and GLY. Various organic acids such as glycolic acid (GCA), oxalic acid (OXA) and formic acid (FA) can be produced in the oxidation pathway of EG.[1] In particular, EG selective oxidation targeted at the production of GCA, which has broad applications in skin care, textile industry and adhesives.

Herein, we fabricated heteroatom doped porous carbons as support materials of highly dispersed Pt nanoparticles and applied to selective oxidation of EG to GCA. By introducing Se in carbon materials, the highly selective production of GCA was achieved with significant conversion of EG over 90%. The porous structure of carbon support led to well dispersed Pt nanoparticle and this morphology was observed by SEM and TEM. XPS and Raman analyses revealed that doped Se atoms changed electronic properties of carbon materials and induced defects into the carbon lattice structure. These properties greatly enhanced the electrocatalytic activity and stability of Pt/SePC, resulting that GCA yield reached to and remained around 85% during several repeated tests for the EG selective oxidation. Our study could highlight favorable strategy of catalyst design with heteroatom doping for ethylene glycol conversion to glycolic acid.

[1] D. Jang, H. Han, J. Maeng, W. Yoon, M. Park and W. B. Kim, Highly active PdSb catalysts on porous carbon for electrochemical oxidation reactions of biomass-derived C1–C3 alcohols, Mater. Adv., 2022, 3, 5964-5973.
Paper-Based Electrodes to Detect Ascorbic Acid, Uric Acid, Dopamine & Biomass Derived Sugars
Authors: Begay Makeiyla , Wilson Katelyn , Charley Jasmine , Platero Justin , Nelwood Michael , Francis Samantha , Mhatre Apurv , Varman Arul Mozhy , Soundappan Thiagarajan
Published: September 2023

Multiple factors are involved in creating an electrochemical sensing device to detect various compounds. There is always a need for environmentally friendly, disposable, flexible, low-cost electrochemical sensor devices. This type of technology in the Navajo Nation is essential because it would allow them to have real-time, reliable, and cost-effective on-site detection. This would allow the Navajo Nation to detect and analyze compounds that may cause severe health issues. We fabricatehand-made flexible paper electrodes at Navajo Technical University (NTU) to detect and determine essentialbiomolecules such as ascorbic acid, dopamine, uric acid, and glucose. The materials required to fabricate these paper-based electrodes are chromatography paper, a wax printer, electrochemically active and conductive ink, electrochemistry equipment, buffer solution, and the compound being tested. First, we would get chromatography paper and print the electrode outline, designed at NTU, using the wax printer. The next step is manually coating the electrodes with the conductive ink and adding gold, copper, silver, or nickel nano-particles, which will act as catalysts. Then we deploy these electrodes to detect Glucose, Uric Acid (UA), Ascorbic Acid (AA), or Dopamine (DA) and test multiple different concentrations. We have utilized various types of electrochemical techniques like Differential pulse voltammetry (DPV), Linear Sweep Voltammetry (LSV), or Cyclic voltammetry (CV). Paper-based electrodes show noticeable results for detecting and determining these target analytes in the lab samples and real sample analysis.
Design and Fabrication of Flexible Paper-Based, Electrochemical Sensors to Detect the Presence of Heavy Metals in Ground Water
Authors: Platero Justin , Soundappan Thiagarajan , Abdelazim Khaled , Nelwood Michael , Wilson Katelyn , Begay Makeiyla , Charley Jasmine , Francis Samantha
Published: September 2023

The history of mining and mineral extraction across the Navajo Nation has resulted in considerable contamination of the land and the groundwater resources, which is a significant environmental concern. Through a partnership between Navajo Technical University and Harvard University, we have designed and fabricated flexible, paper-based sensors in tandem with electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, and anodic stripping voltammetry to determine heavy metal concentrations in test samples. We have selected to fabricate paper-based electrochemical sensors because; they are low-cost, easy to make, environmentally friendly, and can be deployed for field testing across the Navajo Nation. Furthermore, the linear electrochemical response and sensitivity of these electrodes, for detecting heavy metals, makes them well suited for real-time sensors in field-testing applications.
(Keynote) Releasing the Bubbles: Efficient Phase Separation in (Photo-)Electrochemical Devices in Microgravity Environment
Authors: Brinkert Katharina , Romero-Calvo Álvaro , Akay Oemer , Saravanabavan Shaumica , Sokalu Eniola
Published: September 2023

One of the major challenges human space exploration faces is the absence of buoyancy forces in orbit. Consequently, phase separation is severely hindered which impacts a large variety of space technologies including propellant management devices, heat transfer and life support systems e.g., during the production of oxygen and the recycling of carbon dioxide. Of particular interest are hereby (photo-)electrochemical (PEC) devices as they can produce essential chemicals such as oxygen and hydrogen in two set-ups: either, by coupling the electrochemical cell to external photovoltaic cells as currently utilized on the International Space Station or by direct utilization of sunlight in a monolithic device, where integrated semiconductor-electrocatalyst systems carry out the processes of light absorption, charge separation and catalysis in analogy to natural photosynthesis in one system. The latter device is particularly interesting for space applications due to present mass and volume constraints. Here, we discuss two combined approaches to overcome phase separation challenges in (photo-)electrolyzer systems in reduced gravitational environments: using the hydrogen evolution reaction (HER) as a model reaction, we combine nanostructured, hydrophilic electrocatalyst surfaces for efficient gas bubble desorption with magnetically-induced buoyancy to direct the produced hydrogen gas bubbles on specific trajectories away from the (photo-)electrode surface. (Photo-)current-voltage (J-V) profiles obtained in microgravity environments generated for 9.2 s at the Bremen Drop Tower show that our systems can operate with our two-fold approach near terrestrial efficiencies. Simulations of gas bubble trajectories accompany our experimental observations, allowing us to attribute the achieved phase separation in the PEC cells to the increased electrode wettability as well as the systematic use of diamagnetic and Lorentz forces.
(Invited) Ionic Liquid Electrospray Ion Sources for Space Propulsion
Authors: Takao Yoshinori
Published: September 2023

The number of microspacecraft launched has significantly increased since 2013, and more than 300 nano/microsatellites (< 50 kg) were launched in 2017. Although some microspacecraft already have a propulsion system, a commonly used propulsion system is a cold-gas thruster, which has a low delta-v (a few 10s of m/s), and thus, high delta-v (> 1 km/s) thrusters are required for more advanced missions. One of the candidates for such thrusters is ion thrusters, which were already mounted on two 50 kg-class microsatellites and successfully operated in space. However, it is not easy to miniaturize ion thrusters so that they can be mounted on even 10 kg-class nanosatellites unless high-pressure gas-feeding systems are removed. Moreover, ion thrusters require electron sources to neutralize ion beams, which consume additional propellants and power. Since most recently launched microspacecraft are less than 10 kg, more compact thrusters are required. Ionic liquid electrospray ion sources are attractive devices for such electric propulsion, especially for microspacecraft. Electrospray thrusters typically consist of many emitters, an extractor electrode, and an accelerator electrode optionally. When a high voltage between the emitter and the extractor is applied, the ionic liquid is transported to the emitter tips, and a strong electric field deforms the ionic liquid into a conical shape known as a Taylor cone. When the force of the electric field is stronger than the surface tension pressure of the ionic liquid, ions evaporate directly from the liquid surface. The extracted ions are then accelerated by the potential difference between the emitter and extractor to produce the thrust. Since the ionic liquid is composed of only cations and anions without solvent, its vapor pressure is negligible; therefore, it can exist in the liquid phase in vacuum, simplifying the propellant feed system and reducing the size of the entire propulsion system. Moreover, the direct acceleration of ions without discharges can be possible, and no neutralizers are required, which also contributes to the power and size reduction together with high efficiency. The key component of electrospray thrusters is the emitter, where there are typically three types of structures: externally-wetted (or needle-shaped), internally-wetted (or capillary), and porous ones. Each has ion emission characteristics depending on the structure. Here, we have fabricated these three types of emitter structures with a wide range of scale: 1 to 100 micrometers. Using these emitters, we have conducted ion emission experiments and beam diagnostics. We obtained a high current density over a few 10 mA/cm2 with 1-micrometer scale emitters, a high current of approximately 1 mA with porous emitters, and a high efficiency with externally-wetted emitters. The emitter structures as mentioned earlier and experimental results will be presented at the conference site.
(Invited) Electrochemical Approaches for Generating Oxygen on the Moon
Authors: Symes Mark
Published: September 2023

The development of efficient in-situ resource utilizsation (ISRU) processes to generate oxygen on the Moon will be essential for enabling human exploration of the Moon and the wider solar system. In this talk, we will look at electrochemical studies on two different approaches to this goal. The first approach involves the electro-deoxidation of powdered lunar regolith by a Metalysis-FFC-Cambridge approach to produce oxygen and metal alloys (Planet. Space Sci.
2020, 180, 104748;
Planet. Space Sci.
2022, 211, 105408). The resulting metallic powder was found to contain only a very small percentage of oxygen (a portion of which was due to post electrolysis surface re-oxidation) and to consist primarily of Al/Fe(-Si), Fe/Si(-Ti/Al), and Ca/Si/Al(-Mg) alloys. In the second half of the talk, we will examine the efficiency of water electrolysis (and specifically of the oxygen evolving half-reaction) under reduced gravity levels, including lunar gravity, and we will discuss the prospects that these results present for performing electrolysis of water to generate oxygen on the Moon (Nat. Commun.
2022, 13, 583).

Figure 1
On the Viability of Carbon Dioxide in-Situ Resource Utilization (ISRU) to Produce Chemical Feedstocks on Mars
Authors: Usen Nazreen Mohamed Shahid , Sankarasubramanian Shrihari , Chambers Bradley
Published: September 2023

The vision of a sustained human presence in space and extraterrestrial bodies necessitates an ever-larger share of life sustaining materials to be produced by in-situ resource utilization (ISRU). In this context, on Mars, NASA envisions the transformation of Martian atmospheric carbon dioxide into potential feed stocks through a process of climate enhancing resource utilization (with the technology being applicable for CO2 utilization on Earth as well) [1]. Amongst the potential raw materials present on Mars, the presence of stable brines in the liquid phase [2] (due to dissolved perchlorate salts suppressing the freezing point of water to < 213K) along with the availability [3] of 95 vol.% atmospheric CO2, can enable the development of a CO2-H2O electrolyzer to produce CO2 reduction products and O2. In this work, we examine the viability of such an electrolyzer system operating at or near Martian ambient conditions by developing thermodynamic and electrochemical polarization models of this system for various CO2 reduction products. Given the extreme operating conditions, the models were first applied to existing experimental data from an operational water electrolyzer under simulated Martian conditions to evaluate fit [2]. For the proposed CO2-H2O electrolyzer, the Nernst potential for various reactions, the anode/cathode catalysts, their corresponding overpotentials and separator conductivity were calculated or parameterized from experiments in the literature. This was integrated into the polarization model to predict the performance of these electrolyzers under Martian conditions and for various desired products. The polarization curves were calculated for the following possible reaction products; CO (# of e- = 2), HCHO (# of e- = 4), CH3OH (# of e- = 6), CH4 (# of e- = 8), C2H4 and C2H5OH (# of e- = 12) under both Earth and Mars conditions. CH4 and C2H5OH were found to be thermodynamically favored products as compared to other(s) across the range of operational temperatures from 230 K to 298 K. CO, HCHO and C2H4 can serve as potential feed stocks for downstream processing into other useful chemicals on Mars and strategies are discussed for their selective production.

REFERENCES

[1]. NASA, small business innovation research (SBIR) & small business technology transfer (STTR) program, 2022 phase I solicitation

[2].Gayen, P., Sankarasubramanian, S., & Ramani, V. K., Fuel and oxygen harvesting from Martian regolithic brine. Proceedings of the National Academy of Sciences, 117(50), 31685, (2020).

[3].Meyen, Forrest E., et al. "Thermodynamic model of Mars oxygen ISRU experiment (MOXIE)." Acta Astronautica 129, 82 (2016).

Figure 1. Calculated electromotive force of the production of various CO2 reduction products.

Figure 1
Investigation into Anion Effects on the Bulk and Interfacial Solvation Structure for Multivalent Ion Batteries
Authors: Lavan Sydney Nicole , Connell Justin G. , Viswanath Shashwat
Published: September 2023

Zinc ion batteries (ZIB) are attractive because of the relative abundance of Zn as a core earth element, a higher volumetric energy density compared to lithium metal and it is cost effective. Despite this promise, a general lack of fundamental understanding of the electrode-electrolyte interface in ZIB, and multivalent (MV) ion technologies more broadly, hinders their wide scale deployment. In particular, the solvation structure of aqueous and non-aqueous electrolytes plays a critical role in promoting the necessary intermolecular charge transfer interactions to drive reversible plating/stripping at the metal anode. Here we examine the dynamics of the bulk and interfacial solvation structure to uncover differences in the bulk vs. the interfacial speciation as a function of anion chemistry in hopes to develop new design principles for new electrolyte development in ZIB and MV technologies. Utilizing Raman spectroscopy to probe the bulk solvation structures of Zn-based electrolytes containing one anion such as SO4
2-, bis-trifluoromethane sulfonimide (TFSI-) and trifluoromethanesulfonate (triflate, OTf-), we find three solvation environments present; a main feature corresponding to the “free” anion breathing mode and, in some cases, small amounts of mono- or bidentate contact ion pairs (CIPs). In some cases, introduction of co-anions (i.e., halides, X = Cl-, Br-, I-) results in significant extra intensity on the low frequency side of the overall Raman peak envelope that does not correspond with solvation structures observed in the single anion electrolytes. First principles density functional theory (DFT) calculations indicate the additional vibrational mode corresponds to a mixed anion CIP, suggesting anion-anion interactions can induce nominally dissociated anions to coordinate the cation in ways they otherwise would not. Raman and DFT analysis of Mg-based electrolytes indicate similar mixed anion CIP structures are formed, indicating similar solvation effects are active in other MV systems. Preliminary measurements utilizing shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERs) will also be discussed as a means of developing in situ understanding of the evolution of interfacial solvation and surface chemistry during the stripping/plating process. Overall, these results point to new possibilities in controlling the multivalent cation solvation structures present in the bulk and at the interface. This will aid in the development of highly reversible electrolytes that are stable against both divalent metal anodes and high voltage cathodes.
Zinc/ Manganese Oxide Aqueous Electrolyte Batteries: Electrochemical Reaction Mechanisms Beyond Ion Insertion
Authors: Takeuchi Kenneth J. , Takeuchi Esther S. , Marschilok Amy C.
Published: September 2023

The consistent delivery of clean electrical energy is a global challenge where the current electric grid infrastructure distributes electrical energy from the generation source to the end user.

Widespread integration of inherently intermittent renewable energy sources such as wind and solar into the electric grid electrical energy storage into the electric grid demands incorporation of energy storage. Further, energy storage would enable control over when the electrical energy is used improving grid reliability and resiliency. Thus, stationary energy storage for the electric grid is a critical and timely application for batteries.

Rechargeable aqueous zinc/ manganese oxide (Zn/MnO2) batteries are an appealing target for scalable stationary energy storage applications due to their low cost, safety, and environmentally benign components. Notably, manganese oxide is a versatile material where several polymorphs are viable cathode materials in aqueous zinc ion batteries. However, there is need for more complete understanding of the electrochemical reaction mechanisms, to continue to advance the system. This presentation will feature investigations of the reaction mechanisms with a focus on operando methods. X-ray diffraction, Mn K-edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements supported by ex situ transmission electron microscopy (TEM) will be presented. The findings provide a foundation for advancing the battery systems based on aqueous electrolyte zinc anode chemistries suitable for scalable stationary energy storage.
(Invited) Commercialisation of Sustainable Sodium Ion Batteries
Authors: Brant William Robert , Younesi Reza
Published: September 2023

As the world continues to face one crisis after another, the demand for renewable energy and a reliable supply of abundant raw materials is stronger than ever. This is becoming abundantly clear for Li-ion batteries whose adoption in electric vehicles and stationary energy storage is rapidly expanding. In line with this growth, the limited supply of critical raw materials such as Li, Co and Ni is driving up prices. Thus, batteries based on alternate, abundant raw materials are critical. Consequently, in November 2022 IUPAC announced sodium-ion batteries amongst the top ten emerging technologies in Chemistry 2022 [1].

Since 2015 we have been developing a sodium-ion battery prototype with low-cost materials and a keen focus on maintaining safety and sustainability. The battery cell consists of Prussian white (Na2Fe[Fe(CN)6]) as the positive electrode, hard carbon as the negative and sodium bis(oxalate)borate (NaBOB) as fluorine-free salt dissolved in non-flammable alkyl phosphate-based solvents such as triethyl phosphate (TEP) and trimethyl phosphate (TMP) as the electrolyte solution. Our early successes in the low cost synthesis of Prussian white led to the spin-off company ALTRIS which is now focused on the commercialization of sodium-ion batteries. The company has successfully raised funding in seed and Series A funding rounds. With the funding ALTRIS has started construction of an industrial scale manufacturing unit with the annual capacity of 2,000 tonnes of Prussian white to enable 1 GWh of sodium-ion batteries.

Part of the on-going success of Altris is the close collaboration to the research teams within the Ångström Advanced Battery Center and the concurrent developments of material understanding and pilot industrial scale implementation. In this contribution an update of the company progress will be presented including a brief history as well as future plans for cell production. A focus will be placed on how fundamental investigations at Uppsala University are accelerating material development for solving problems such as moisture sensitivity and structural degradation.

[1] Gomollón-Bel, F., Chem. Int.
2022, 44(4), 4
Fulfilling the High Capacity of Zn Anodes in Rechargeable Alkaline Zn Batteries
Authors: Chen Qing , Li Liangyu , Ma Yilin
Published: September 2023

A Zn anode in an alkaline electrolyte is often discharged to a shallow depth for an adequate cycle life. It limits the overall cell energy density and undermines its competitiveness against ever-improving lithium-ion cells. Our lab has been pushing the capacity limit of the alkaline Zn anode by understanding its failure mechanism and designing electrode microstructures and electrolyte alkalinity. I will discuss how we can revamp the paths of phase transition between Zn and ZnO by building a bi-continuous porous Zn anode and how a super-alkaline electrolyte can stabilize the anode at 60% depth of discharge. The mechanisms underlying the designs, including the interface-controlled structural evolution and the structural diffusion of alkaline electrolytes, will be explained to shed light on the future development of rechargeable Zn batteries.

References:

1. Li, L.; Tsang, Y. C. A.; Xiao, D.; Zhu, G.; Zhi, C.; Chen, Q. Phase-Transition Tailored Nanoporous Zinc Metal Electrodes for Rechargeable Alkaline Zinc-Nickel Oxide Hydroxide and Zinc-Air Batteries. Nat Commun
2022, 13, 2870.

2. Zhu, G.; Xiao, D.; Chen, Q. Spontaneous Formation of Porous Zinc in Rechargeable Zinc Batteries. J.
Electrochem. Soc.
2021, 168, 110524.
Performance Comparison of Three Polymer Electrolytes for Zinc Ion Batteries
Authors: Rajabi Roya , Sun Shichen , Huang Kevin
Published: September 2023

With the increasing demand for zinc ion batteries working over a wider temperature range, several electrolyte strategies have been proposed, including organic additives, water-in-salt solutions, and polymers. However, organic additives typically decrease the ionic conductivity of the aqueous electrolyte, while highly concentrated salts (water-in-salt) decrease electrolytes’ wettability and raise the cost. In contrast, polymer electrolytes are an appealing option. They are resistant to zinc dendrite attack and side reactions and maintain a good electrode-electrolyte interface. They are also flexible, making them suitable for soft electronics applications. In this presentation, we compare the properties of three polymer membranes as electrolytes: polysaccharides carboxymethyl chitosan-based hydrogel, polybenzimidazole, and polyvinyl alcohol-based hydrogels. We also show their interactions with zinc perchloride (Zn(ClO4)2), a high-conductive zinc salt, to enable low-temperature performance. The chaotropic activity of ClO4
- anion, as well as the formation of ternary and weak hydrogen bonds (HB) with water and polymer chains, are described to aid in the reduction of free water and anti-freezing performance at subzero temperatures.
Enabling Fe+2.5 to Fe+3 Redox Reaction in Prussian Blue Materials for High-Performance Aqueous Sodium-Ion Batteries
Authors: Lucero Marcos , Li Xiaolin
Published: September 2023

Aqueous Na-ion batteries using Prussian blue materials have intrinsic advantages on safety, material sustainability, and economic cost. However, it is challenging to obtain long term cycling stability because many redox reactions have poor intrinsic stability in water. Here, we enable Fe+2.5 to Fe+3 redox reaction in Prussian blue materials by converting the monoclinic sodium iron hexacyanoferrate (m-Na1.81Fe[Fe(CN)6]·0.7H2O) to a cubic phase (c- Na1.17Fe[Fe(CN)6]·0.7H2O) and demonstrated high performance by cycling in a water-in-salt electrolyte. Systematic characterization including electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy have verified the phase transition and iron oxidization state evolution. The cubic phase Na1.17Fe[Fe(CN)6]·0.7H2O delivers excellent cycling stability of >18,000 cycles with >90% capacity retention. The specific capacity is ~75 mAh/g and ~67 mAh/g at 1C and 10C rate, respectively.
(Invited) Mechanistic Understandings of Interfacial Instabilities of Na and Zn Metal Anodes in Liquid Electrolytes
Authors: Bai Peng
Published: September 2023

Next-generation high-energy batteries require rechargeable metal anodes, but hazardous dendrites tend to form during recharging, causing short-circuiting risks and capacity loss. In this presentation, we will exploit our understanding of lithium whiskers and dendrites to investigate the interfacial instabilities of Na metal anode and Zn metal anode, through the intimate combination of operando microscopy and novel transport models. Our results demonstrate the necessity to carefully avoid the transport-controlled scenario, in which fast-advancing dendritic growths would become inevitable to short the cell. Within the reaction-controlled regime, however, resolving the interfacial instability and metal whiskers leads to ideally smooth, non-porous, ingot-type Na metal plating, which enabled the anode-free Na metal full cells with a record-high capacity retention rate of 99.93% per cycle at 3C charge and discharge. Chronopotentiometry tests of this ideal metal electrode revealed an inverse correlation between the penetration overpotential and the pore size of the separator, which can be captured by a new model we named as the Young-Laplace critical overpotential. Following a similar principle, we investigated the growth of Zn dendrites in operando in our capillary cells. We discovered for the first time that seemingly negligible pore-wall charges, far away from the bulk electrolyte, can affect the morphology of Zn dendrites, which suggests that by depositing negative and positive charges on the pore walls, a bipolar separator not only can ensure uniform cation flux to improve the interfacial stability but also can stop localized dendrite penetration autonomously toward ideal safety.
An Exploration of the Sodium Solid Electrolyte Interphase in Glyme Electrolytes with Carbonate Additives
Authors: Sarkar Susmita , Lefler Matthew Jacob , Vishnugopi Bairav Sabarish , Love Corey T. , Carter Rachel Elizabeth , Mukherjee Partha P.
Published: September 2023

The utilization of alkali metal anodes is hindered by an inherent instability in organic electrolytes. Sodium (Na) is of growing interest due to its high natural abundance, but the carbonate electrolytes that are popular in lithium systems are unable to form a stable solid electrolyte interphase (SEI) with a sodium metal electrode. However, the glyme (chain ether) electrolytes produce thin, predominantly inorganic SEI at sodium metal interfaces. Using half-cell and symmetric cell analysis, we identify diglyme (G2) as the best performing of the glymes, balancing the high nucleation barrier of the short glyme (G1) and the high plateau overpotential of the long glyme (G4). Based on mesoscale modeling, we capture the critical dependence of the nucleation and early-stage growth morphology on a competing set of mechanisms, including the reduction kinetics on the substrate/newly deposited Na and the surface mobility of these deposits. Through in situ optical microscopy, the onset and growth of Na dendrites is revealed in glyme electrolytes, and the addition of small quantities (~10% volume/volume) of ethylene carbonate (EC) and fluoroethylene carbonate (FEC) to G2 is shown to facilitate uniform sodium plating characteristics in the optical cell, presumably through alterations to SEI composition. X-ray photoelectron spectroscopy (XPS) analysis reveals that the FEC additive results in an SEI with similar atomic composition to that formed in G2 alone, whereas addition of EC to G2 results in an entirely different SEI composition, despite the molecular similarity of the carbonate additives. We have determined that the SEI formed by glyme alone may not support extensive or extreme cycling conditions, but the addition of FEC provides a much more robust SEI at the Na metal surface to facilitate numerous consistent sodium plating and stripping cycles.
Molten Sodium Batteries – Lewis Acidity of AlCl3/NaI Catholyte Impedes NaSICON Interface
Authors: Maraschky Adam M. , Meyerson Melissa L , Percival Stephen J. , Peretti Amanda S. , Spoerke Erik D. , Small Leo J.
Published: September 2023

Low temperature molten sodium batteries with sodium metal anodes, NaSICON solid-state separators, and sodium halide salt catholytes are low cost, earth-abundant technologies for grid-scale energy storage.1-3 We compared batteries with NaI/AlCl3-based molten salt catholytes of differing Lewis acidities at 110 °C. Batteries with >50 mol% AlCl3 (acidic catholytes) experienced a linear decline in energy efficiency during cycling, whereas batteries with >50 mol% NaI (basic catholytes) maintained 95% energy efficiency for 100 cycles (5 months) at 2.5 mA cm-2. A 3-electrode cell was developed, enabling electrochemical identification of the NaSICON-catholyte interface as the source of increased impedance. Complementary physical and chemical characterization of the NaSICON exposed to acidic and basic catholytes showed no changes in crystallinity, bulk morphology, or bulk chemical composition, but surface sensitive X-ray photoelectron spectroscopy (XPS) revealed subtle changes in the local NaSICON surface chemistry. In addition, Raman spectroscopy indicated that basic catholytes lack the dimer species Al2Cl6I- present in acidic catholytes. These results suggest that one means to enable efficient and stable battery cycling is maintaining Lewis-basic NaI/AlCl3, which avoids deleterious interactions at the NaSICON-catholyte interface. Recent progress towards achieving high cycling rates in these molten salt systems will also be shared.

References

L. J. Small, A. Eccleston, J. Lamb, A. C. Read, M. Robins, T. Meaders, D. Ingersoll, P. G. Clem, S. Bhavaraju and E. D. Spoerke, J. Power Sources, 360, 569 (2017).

S. J. Percival, L. J. Small and E. D. Spoerke, J. Electrochem. Soc., 165, A3531 (2018).

M. M. Gross, S. J. Percival, L. J. Small, J. Lamb, A. S. Peretti and E. D. Spoerke, ACS Appl. Energy Mater., 3, 11456 (2020).

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
Synthesis and Thermal Evaporation Deposition of Sodium Oxychloride Solid-State Electrolyte for Sodium-Ion Batteries
Authors: Ly Karen , Zheng Fan , Smirnova Alevtina
Published: September 2023

Sodium-ion batteries have attracted significant attention by offering an alternative option to lithium-ion batteries. Solid-state sodium oxyhalides (Na3OX, X = Cl, Br, I) have the advantage of cost-effective synthesis from raw materials in a time-effective manner. In this study, sodium oxychloride (Na3OCl) antiperovskite was synthesized using a novel approach that allowed for facile synthesis outside of an argon glovebox. The ionic conductivity of Na3OCl pellets compressed between graphite-coated copper foil was tested in the temperature range of 160˚C and 200˚C using electrochemical impedance spectroscopy (EIS). Arrhenius plots demonstrated linear behavior in the whole temperature range with a calculated activation energy of 0.98 eV. At lower temperatures, EIS data was not available likely due to high impedance from the thickness of the electrolyte pellet, high activation energy, or slow migration of sodium ions through the Na3OCl structure. To decrease electrolyte thickness, we implement physical vapor deposition (PVD) thermal evaporation to coat thin films (<100 µm) of the electrolyte onto graphite-coated copper foil and sodium-based cathodes for use in symmetric cell and half-cell configurations. The melting and crystallization temperatures were determined using differential scanning calorimetry (DSC). The purity of as-synthesized sodium oxychloride and PVD-deposited layer was evaluated using X-ray diffraction (XRD). The results on chemical composition and crystal-to-glass phase transformations are produced from in-situ X-ray diffraction (XRD) spectroscopy in the temperature range from 25˚C up to the melting point of Na3OCl. Cross-sectional SEM images of PVD-deposited sodium oxychloride showed an even distribution of sodium, oxygen, and chlorine. However, XRD analysis of deposited layers showed that sodium oxychloride had a tendency to decompose into the precursors during deposition. This work is focused on maintaining the sodium oxychloride composition and structure during PVD thermal evaporation by optimizing the PVD deposition parameters.

The authors acknowledge financial support from the NSF IUCRC program for the “Center for solid-state electric power storage” (#2052631) and support from the South Dakota Board of Regents for the “Governor’s Research Center (GRC) for electrochemical energy storage”.