bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion Transport and Electrochemical Stability of Polyacrylonitrile (PAN) Based Electrolytes
Authors: Chen Xi , Liu Changhao , Sacci Robert L , Sahore Ritu , Dudney Nancy , Veith Gabriel M.
Published: November 2022

Polyacrylonitrile (PAN) is one of the alternative candidate polymer hosts to form solid polymer electrolytes (SPEs) besides the widely used poly(ethylene oxide). However, over 3 orders of magnitude of discrepancy in ionic conductivity has been reported in PAN-based SPEs, in both the low salt concentration and the high salt concentration regimes. This discrepancy originates from different film processing conditions. In this study, we rigorously examine how processing conditions, including solution mixing, casting, and drying conditions affect the morphology, ion transport, solvation structure, Li and oxidative stability of PAN based electrolytes. It is found that the ion transport, lithium stability and the oxidative stability of PAN-based SPEs are critically dependent on the residual dimethylformamide (DMF) solvent content. We systematically study four different drying conditions and the resulting residual solvent is quantified by infrared spectroscopy. We demonstrate that conductivity variation across 5 orders of magnitude can be obtained depending on the drying conditions. Furthermore, the effects of residual DMF solvent on the ion transport mechanism, stability against lithium and the oxidative stability are elucidated. This thorough study lays the groundwork for future development of PAN based electrolytes.
Electrochemical Characterization of a Drawn Thin-Film Glassy Mixed Oxy-Sulfide-Nitride Phosphate Electrolyte for Applications in Solid-State Batteries
Authors: Martin Madison , Okkema Mary , Martin Steve
Published: November 2022

Thin-film glassy solid-state electrolytes (GSEs) are being considered for applications in energy storage devices; fully-dense thin-film glassy electrolyte materials are able to minimize power loss while suppressing dendrite growth. The glass with the composition Na4P2S5.8O0.92N0.18 (NaPSON) was chosen because it balances the high conductivity of a sulfide chemistry with the high processability and electrochemical stability of an oxy-nitride chemistry. NaPSON thin-film GSE ribbons with thicknesses that range from 50 to 150 μm were drawn using a process of softening and drawing of a cast and annealed preform. Electrochemical impedance spectroscopy (EIS) was used on varying thicknesses of thin-film to investigate and compare the ionic conductivity of Na+ in the thin film compared to the bulk sample. Area specific resistance models as a function of time were created to compare the trend of bulk and interfacial resistances of different thicknesses. Thin-film samples were made into symmetric cells and cycled. The cycling of the symmetric cells gave insight into the behavior and durability of the electrolyte under applied voltage and sustained current. These results show that drawn thin-film electrolytes are a viable research direction for all solid-state batteries.
Organosulfur Cathodes with High Compatibility in Carbonate Ester Electrolytes for Long Cycle Lithium–Sulfur Batteries
Authors: Weret Misganaw Adigo , Su Wei-Nien , Hwang Bing-Joe
Published: November 2022

Lithium-sulfur batteries (LSBs) are potential candidates for high energy storage technologies due to their theoretical gravimetric energy density of ∼2600 Wh kg-1 and lightweight electrodes. In LSBs, ether electrolytes are frequently utilized because sulfur cathodes and the polysulfide redox intermediate species are chemically stable. However, LSBs in ether electrolytes suffer from the dissolution of higher-order polysulfides, and migration of the soluble polysulfides into electrolytes causes the polysulfide shuttle effect. The shuttle polysulfides react with the lithium anode and give rise to the irreversible deposition of lithium sulfides, deteriorate the morphology of the anode, and cause rapid capacity fading. Moreover, ether electrolytes are highly flammable and trigger safety issues. As an alternative, carbonate ester electrolytes are promising choices to substitute ether electrolytes in LSBs. Organic carbonate electrolytes used in LSBs result in irreversible reactions with long-chain polysulfide anions that cause the cell to shut down. Therefore, carbonate ester electrolytes compatible sulfur cathodes design needs special attention. Sulfurized polyacrylonitrile (SPAN) and short-chain sulfur cathodes are compatible with organic carbonate electrolytes. However, the sulfur contents in these cathodes are mostly below 50 wt% which hamper the practical application of the LSBs. Here, we designed an organosulfur cathode with a high chemical bonded sulfur content of ~58 wt% in the cathode composite. The prepared organosulfur cathode showed excellent compatibility with carbonate ester electrolytes. The organosulfur cathode exhibits a high initial discharge capacity of 1301 mAh g-1 and long cycle stability for 400 cycles with nearly 99.99% coulombic efficiency.
High Capacity Lithium-Sulfur Batteries (> 12 mAh cm–2) Enabled By 3D-Compact Sulfur Cathode and Polysulfide Adjoining Interface Engineering
Authors: Kim Hun , Ham Young-Geun , Sun Yang-Kook
Published: November 2022

Beyond the theoretical limitation of current Li-ion batteries technology, there have been large efforts to develop practical next-generation batteries. Among them, lithium-sulfur (Li-S) batteries have been eagerly studied due to their attractive features; the low cost and expected high energy density. To maximize the energy density of Li−S batteries, it is crucial to increase the loading level of sulfur cathode and minimize the electrolyte content. However, excessive amounts of lithium polysulfides (LiPSs) generated in the high loading Li-S batteries limit the stable cycling. In this study, a high-loading S cathode (15 mg cm−2) with a three-dimensional (3D) network structure is fabricated using a simple pelletizing method, and the exhausting overcharging phenomenon, which occurs in the high loading Li−S cell, is successively prevented by pre-treating the lithium metal anode. Moreover, adding a diluent to the electrolyte containing viscous LiPSs enables the facile conversion between S species during the cycling of high loading Li−S cells under lean electrolyte conditions. Finally, a prototype Li−S pouch cell with high energy density (427 Wh kg−1) was realized by combining a compacted 3D cathode with a high-loading, pretreated thin lithium metal and diluent-modified electrolyte. We believe that the results reported herein will be a good guideline to establish proper strategies to achieve high energy density Li−S batteries.

Reference
s
:

[1] J.-Y. Hwang, S. Shin, C. S. Yoon, Y.-K. Sun, ACS Energy Lett. 4 (2019) 2787–2795.

[2] J.-Y. Hwang, S.-J. Park, C. S. Yoon, Y.-K. Sun, Energy Environ. Sci. 12 (2019) 2174–2784.

[3] H. Kim, S. Bang, K.-J. Min, Y.-G. Ham, S.-J. Park and Y.-K. Sun, ACS Appl. Mater. Interfaces 13 (2021) 39435–39445.
Nickel Cobalt Oxide Decorated Cerium Oxide Nanorods for Polysulfide Trapping and Catalytic Conversion in Advanced Lithium Sulfur Batteries
Authors: Azam Sakibul , Wei Zhen , Wang Ruigang
Published: November 2022

Lithium sulfur batteries (LSBs) are promising candidates for next-generation rechargeable batteries due to the active material sulfur being earth abundant, low cost and environmentally friendly element. But the most important feature of LSBs is that the theoretical capacity of sulfur is ~1645 mAh g-1 which is ~5 times higher than the conventional lithium-ion batteries. However, even with these valuable assets, LSB has not yet been commercialized due to the inherent problems of fast capacity loss resulting in low cycle lifetime. This capacity loss originates from the migration of dissolved sulfur discharge products in the electrolyte known as the notorious polysulfide shuttling effect.

To deal with this issue, several research efforts have been made to trap the high order lithium polysulfides by a) physically encapsulation using high surface area carbonaceous materials and b) chemically binding the lithium polysulfides in its cathode host. Several materials are very popular to efficiently bind the lithium polysulfides such as transition metal oxides, nitrides, sulfides and have helped making significant advances to long cycle life lithium sulfur batteries. However, to make the transition to design next generation LSBs, there is a need for materials that can facilitate fast polysulfide conversion by catalytic reaction that will reduce the diffusion and agglomeration of polysulfides in the liquid organic electrolyte, resulting in high capacity and long cycle lifetime.

With this strategy in mind, we have designed NiCoOx decorated on CeO2 nanorods support as cathode host material for LSBs to provide dual adsorption-catalysis synergy. The CeO2 nanorods with enriched surface defects can effectively bind the lithium polysulfides whereas the NiCoOx nanoclusters can provide highly efficient electrocatalytic sites to improve the conversion kinetics of elemental sulfur to high order lithium polysulfides to finally the lower order polysulfides. As a result, the derived LSBs exhibited excellent electrochemical performance with high capacity of 1236 mAh g-1 at 0.2C with a sulfur loading of 1.33 mg cm-2. Even with high sulfur loading 2.66 mg cm-2 the LSBs exhibits 755 mAh g-1 at 0.2C with a capacity decay of only 0.08% per cycle after 170 cycles. The battery also operates at the sulfur loading of 4 mg cm-2 and 5.33 mg cm-2 for more than 100 which is convincing considering commercialization of LSB.

Key words:
lithium sulfur batteries, lithium polysulfides, shuttle effect, cerium oxide, catalysis.
Biomass-Derived Carbon for High-Performance Lithium-Sulfur Batteries
Authors: Yang Jian , Hansen Zachary , Jamal Maruj , Mathew Kevin , Wang Guanyi , Xiong Jie , Zhou Tiffany , Wu Qingliu
Published: November 2022

With the advantages of high conductivity and low cost, porous carbons have been considered as the most attractive materials as hosts of sulfur cathode in lithium-sulfur batteries (LSBs). However, LSBs always suffer short cycle life due to the “shuttle effect” of lithium polysulfide species (polysulfides), which are intermediate products during the charge/discharge processes. The weak interaction between carbon and polysulfides results in the dissolution of polysulfides from the cathodes, loss of active material and eventually fast capacity fading. To overcome these drawbacks, we employed a biomass-derived carbon as the host material in sulfur cathodes. Results from X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen sorption reveals that this biomass-derived product is amorphous carbon and is composed of both large (>10 nm) and small (<5 nm) pores. Using as hosts of cathodes in LSBs, the biomass-derived carbons could deliver a high reversible capacity of > 800 mAh/g and retain >80% of initial capacity after 200 cycles. Especially, the activated carbons exhibited 80% capacity retention after 400 cycles. The promising LSB performance could be ascribed to the unique porous architecture of biomass-derived carbons. The meso/micropores in biomass-derived carbons could provide more sites to anchor sulfur and polysulfides, while macropores provide channels for fast transport of ions. This was corroborated by the results from the electrochemical impedance spectroscopy (EIS), the thermogravimetric analysis (TGA) and absorption measurements.
(Invited) Lithium – Sulfur Batteries
Authors: Thangadurai Venkataraman
Published: November 2022

These days, Li-S battery has been arisen as one of the key energy storage technologies due to its high theoretical energy density compared to conventional lithium and sodium ion-based batteries. The present Li-S batteries suffer due to Li dendrite formation and capacity decay due to polysulfide dissolution effect, due to organic electrolytes used in the current research. Solid state (ceramic) electrolytes are promising to prevent Li dendrite growth and polysulfide dissolution. Among different ceramic electrolytes garnet-type structure solid inorganic electrolytes are very promising because of its high lithium-ion conductivity and stability with elemental Li. However, the high interfacial resistance with the electrode is the major bottleneck for the practical use of ceramic electrolyte. Polymer and ceramic hybrid electrolytes exhibit low interfacial resistance. In this talk, we will present development of novel hybrid electrolytes for all-solid-state Li-S batteries, along with new methods to produce S cathodes with minimal polysulfide shuttle effect.
Microemulsions As Emerging Electrolytes: The Correlation of Structure to Electrochemical Response
Authors: Imel Adam , Barth Brian , Heroux Luke , Hayes Doug , Dadmun Mark , Zawodzinski Thomas A.
Published: November 2022

Microemulsions are a breakthrough electrolyte for energy storage (BEES) that is emerging as an alternative to traditional RFB electrolytes because of their ability to produce thermodynamically stable, homogeneous solutions of polar and non-polar molecules. The stabilization of oil and water solutions allows microemulsion electrolytes to accommodate organic redox species with fast electron transfer rates that are not soluble in the aqueous phase while still offering the high conductivity of an aqueous salt electrolyte. Microemulsion electrolytes consist of two immiscible phases stabilized by a surfactant, a non-polar phase, solubilizing the redox material—or the redox material can be the entire oil phase—and an aqueous brine phase. Moreover, each component can be environmentally and biologically safe. For example, the aqueous phase only consists of salt and water, the surfactant used in this study, polysorbate-20, is found in many cosmetics and food products, and some of the redox materials investigated in our lab are vitamins such as menadione (vitamin K3) and tocopherol (vitamin E).

Microemulsions form many self-assembled bulk nanoscale structures, such as oil-in-water or water-in-oil droplets and bicontinuous. Furthermore, microemulsions exhibit ordering near surfaces that can be different from the bulk structure. Understanding the bulk and surface structures is critical to understanding a material's properties, such as conductivity and diffusion to an electrode surface. Understanding structural changes with composition variation and surface hydrophobicity provide a path to optimizing the balance between acceptable conductivity levels in the electrolyte and the high volume of an oil phase bearing the redox-active species in a µE. This optimization is critical to achieving high-performing electrochemical systems using µEs.

This talk describes structural studies of microemulsions prepared from water, toluene, butanol, and polysorbate-20. Small-angle neutron scattering was used to monitor the development of the bicontinuous system as a function of the water-to-surfactant mass ratio on a constant oil-to-surfactant dilution line, revealing how the domain size, correlation length, amphiphilicity factor, and bending moduli change with composition. Kratky and Porod analyses are also employed, providing further structural detail of the scattering domains. We demonstrate that controlling the water-to-surfactant ratio with a constant oil-to-surfactant dilution affects the bicontinuous phase, reveals a sizeable compositional region with structural similarities, and provides insight into the correlation of structure to physical properties. Additionally, neutron reflectivity was used to probe the surface ordering of the microemulsions with hydrophilic and amphiphilic surfaces.

Figure 1
(Invited) Anion Conducting Solid Polymer Ionomers Electrolytes for Fuel Cells and Electrolyzers
Authors: Kohl Paul , Mandal Mrinmay , Chen Mengjie , Park Habin , Shah Parin
Published: November 2022

Ion conducting polymer electrolytes provide an enabling technology for the creation of low temperature fuel cells, hydrogen producing water electrolyzers, and flow batteries. The critical parameters of solid polymer electrolytes include ionic conductivity, ion selectivity, chemical resistance and dimensional stability in the presence of excess water. High pH operation using anion conductive polymer electrolytes has several potential advantages over acid-based polymer devices including low-cost catalysts, hydrocarbon (non-perfluorinated) polymer, and low cost cell components. However, the identification and synthesis of stable, hydroxide conducting solid polymer electrolytes has been elusive.

In this study, a family of hydroxide conducting, poly(norbornene) solid polymer electrolytes were synthesized and used in high-performance, durable membrane electrode assemblies for fuel cells and electrolyzers. In addition to membranes, covalently bonded, self-adherent, hydroxide conducting ionomers were used to form high-performance, durable membrane electrode assembly for water electrolysis. Electrodes made by grind-spray method were compared to electrodes prepared by the solvent-cast method. The self-adhesive ionomers and membranes are based on hydroxide conducting poly(norbornene) polymers. The effect of porous transport layer material and porosity was examined. High performance electrolysis with very low degradation rates was achieved using stainless steel and nickel porous transport layers.
Unusual Cation-Pi Solute Interactions with Deep Eutectic Solvents
Authors: Elgammal Ramez A. , Foister Shane , Zawodzinski Thomas A.
Published: November 2022

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, high viscosity while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen box acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBD, the DES forms a eutectic mixture resulting in a large melting point depression due to extensive hydrogen bonding between the components.

Despite being widely studied, the use and subsequent characterization of DESs as solvents for aromatic phenols and related aromatics has only recently received attention. In this study we have investigated the solubility of a broad class of aromatic solutes as a function of DES composition and solute concentration using 1H, 13C, pulsed field gradient (PFG), and nuclear Overhauser effect (NOE) NMR. The degree to which homogenous mixtures versus heterogeneous and/or multi-phase systems are formed as a function of solute, temperature, and DES composition is examined. Two classes of DESs glyceline (glycerol + choline chloride) and ethaline (ethylene glycol + choline chloride) were investigated.

As many as three distinct phases depending on the nature of the aromatic solute are observed by NMR. {1H-1H}-NOESY measurements show strong correlations between the choline chloride ammonium cation and the aryl protons with cation-pi interactions disrupting the hydrogen bonding network of the DES. We will discuss the implications for these systems as green solvents and comment on how clustering of solutes on the nanoscale may find use in catalysis and self-assembly.
(Invited) Highly Performing Protonic Ceramic Fuel Cells with Stoichiometric Electrolytes
Authors: Lee Wonyoung , Choi Mingi , Paik Jaedeok , Woo Deokyoon , Lee Jaeyeob , Kim Seo Ju , Lee Jongseo
Published: November 2022

Among various types of solid oxide electrochemical cells, protonic ceramic fuel cells (PCFCs) have been expected to reduce the operating temperature below 600 °C with their significantly high ionic conductivity and activation energy. For example, recently developed proton conductor (BaZr0.4Ce0.4Y0.1Yb0.1O3-δ, BZCYYb) ideally has ~12-fold higher ionic conductivity (2.810-2 S/cm at 600 °C) and low activation energy (Ea < 0.4 eV) than those of conventional oxide ion conductor (Y0.08Zr0.92O2-δ; 2.810-3 S/cm at 600 °C and Ea ~0.87 eV). However, the low chemical and physical stabilities of proton conducting oxides during fabrication processes, primarily due to the high mobility and volatility of Barium (Ba), induce the substantially lower electrochemical performance than their predictions, limiting their utilization and application. Here, we present the chemically and physically stable BZCYYb electrolyte with the desired stoichiometry and the average grain size of ~10 µm by controlling the chemical potential of the A-site cation, Ba, near the BZCYYb electrolyte surface during the sintering process. A stoichiometric BZCYYb-based PCFC in an anode-supported configuration exhibits 1.90/cm2 and 1.01 W/cm2 with an extremely low ohmic resistance of ~0.060 ohm·cm2 at 650 °C and ~0.082 ohm·cm2 at 550 °C, respectively, surpassing the values of all previously reported PCFCs without complicated engineering in materials and structures of other cell components.
(Invited) Effect of Atomic-Scale Surface Overcoat By Atomic Layer Deposition on Dopant Segregation of Perovskite Cathodes
Authors: Li Haoyu , Garcia ThomasJae , Kang Hung-Sen , Liu Ziqi , Lee Min Hwan
Published: November 2022

Intense research has been performed to advance the solid oxide cell (SOC) technology because of their excellent efficiency for clean energy conversion and storage, but the lack of long-term durability, particularly of perovskite (ABO3)-based air electrodes, is currently the main technological bottleneck for wider commercial adoption. Long-term durability of SOC air electrodes has been mainly hampered by surface segregation of A-site dopant and morphological agglomeration. Since a deposition of an atomically thin oxide has proven to be highly effective in suppressing electrode agglomeration, a successful suppression of dopant segregation with the same approach will enhance the durability of air electrodes significantly by killing two birds with one stone. In the previous study [1], we demonstrated the effectiveness of an atomic scale overcoat in suppressing particle agglomeration.

In this presentation, we demonstrate that even a few angstroms of metal oxide overcoat by atomic layer deposition (ALD) affects the behavior of Sr segregation in the underlying La0.8Sr0.2MnO3 (LSM) electrode significantly. By leveraging angle-resolved X-ray photoelectron spectroscopy (ARXPS), we provide a quantitative analysis of the relative atomic concentration on both the very surface and bulk of the electrode. Compared to bare LSM electrodes, those with 2 – 3 Å ALD overcoat show relatively high resistivity against Sr segregation when exposed to of 750 °C for 250 h. Particularly, an oxide overcoat with multi-valent cations (CeO2 and TiO2) tends to suppress Sr segregation effectively and even drive Sr species back into the bulk of LSM while an overcoat with single valent cations (ZrO2 and Y2O3) exhibits little effect on Sr segregation. It was further demonstrated that the segregation behavior is nicely aligned with the electrode performance; those coated with CeO2 and TiO2 showed better thermal stability in terms of polarization resistance. Based upon the time evolution of Sr content, cationic valence states, and oxygen defect concentration in the vicinity of surface, we conjecture that the amount of oxygen defects formed by the overcoat and the resulting chemical potential gradient at the interface between the overcoat underlying LSM surface plays a pivotal role in the Sr segregation behavior.

The authors acknowledge the support from National Science Foundation (DMR 1753383) and NASA MIRO program (NNX15AQ01A).

References:

Li, H. et al. J. Mater. Chem. A, 8, 15927–15935, 2020.
(Invited) 3D Printed Carbon Microlattices As Electrodes in Electrochemical Cells
Authors: Torgersen Jan , Sauermoser Marco , Baglo Kjetil , Flaten Andreas , Veldurthi Naresh
Published: November 2022

With unprecedented freedom in materials design, additive manufacturing (AM) technologies provide us with the capabilities to leverage from geometric complexity. If properly exploited, this allows us to design performance instead of geometry, where the latter is not user defined but a result of a computer optimization. Entirely new mathematically defined, dimensionally stable carbon materials are presented that shrink isotopically under a pyrolysis process generating complex CAD defined 3D shapes with theoretically two to three orders of magnitude increases in permeability and ohmic conductance over conventional Gas Diffusion Layers. The shown lattices can be structured with resolution in the 10 µm regime having total dimensions over several cm. Initial performance tests in full cell configurations inside a PEMFC are presented. The area of mathematically defined, ordered materials with predictable and optimized performances might shape an entirely research field relevant for low cost and high-performance energy converters.

Figure 1
(Invited) Enhancing Oxygen Reduction Reaction Activities of Pt Catalysts By Atomic Layer Deposited Metal Oxides
Authors: Xu Shicheng
Published: November 2022

The oxygen reduction reaction (ORR) posts a significant kinetic limit to hydrogen fuel cells, especially for polymer electrolyte membrane fuel cells (PEMFCs) operating at low temperatures. Highly active and durable electrocatalysts are required for reducing platinum group metal use and ensuring reliable device performance. The use of atomic layer deposition (ALD) and ALD transition metal oxides as dopants or templates are applied in controlled synthesis of highly active and durable Pt ORR catalysts. With density functional theory, these catalysts can also be designed with reliable theoretical guidance. The feasibility of their use in membrane electrode assemblies will be demonstrated.
The Impact of Residual Solvent on the Performance of Catholyte for Solid-State Batteries
Authors: Shen Fengyu , Jonson Robert A , Tucker Mike C
Published: November 2022

All-solid-state batteries (ASSBs) are attracting more attention in recent years due to their safety, use of Li metal anode, higher energy density, and so on. However, high interfacial resistance, especially on the cathode side, is one of the major challenges to commercialize ASSBs. Catholyte, both liquid or solid, is added to lower the cathode/electrolyte interfacial resistance. In this study, we found residual solvent remaining in a solid polymer catholyte after incomplete drying can dramatically lower the interfacial resistance between LLZO electrolyte and NMC cathode active material. Cells with different amounts of residual solvent are compared to optimize the solvent loading. With residual solvent, the capacity can reach 135 mA h/g when cycled at 25 °C and 0.5 C. Capacity retention is more than 60% after 125 cycles. The cell performs even better at low temperatures than a cell with liquid catholyte. This study demonstrates the possibility of widely differing results for ASSBs when the cathode is not completely dried. Also, it provides a hint for a potential method to lower the cathode/electrolyte interfacial resistance.
(Invited) Garnet Solid Electrolytes for Advanced All-Solid-State Li Metal Batteries
Authors: Thangadurai Venkataraman
Published: November 2022

These days, Li metal anode-based battery has been arisen as one of the key energy storage technologies due to its high theoretical energy density compared to conventional lithium and sodium ion-based batteries. The present Li-S batteries suffer due to Li dendrite formation and capacity decay due to polysulfide dissolution effect, because of organic electrolytes used in the current research. Solid state (ceramic) electrolytes are promising to prevent Li dendrite growth and polysulfide dissolution. Among different ceramic electrolytes garnet-type structure solid inorganic electrolytes are very promising because of its high lithium-ion conductivity and stability with elemental Li. However, the high interfacial resistance with the electrode is the major bottleneck for the practical use of ceramic electrolyte. Polymer and ceramic hybrid electrolytes exhibit low interfacial resistance. In this talk, we will present development of electrolytes for all-solid-state Li metal batteries.
All-Inkjet-Printed Thin-Film Solid Oxide Fuel Cell
Authors: Han Gwon Deok , Han Hyun Soo , Chaikasetsin Settasit , Jung Yunha , Trettel Howard Tyler , Prinz Fritz , Shim Joon Hyung
Published: November 2022

Inkjet printing is a rapid prototyping tool that allows users to easily and quickly produce thin-film devices with inks containing desired functional materials. For example, users can use Computer-Aided Design or MS Office software to draw a pattern image and then simply "print" it to create wide, complex thin film devices made of a variety of functional materials. Therefore, inkjet printing can be effectively used to design and prototype thin film-based solid state devices for evaluating the properties of ion-conducting membranes or electrocatalysts.

Solid oxide fuel cells (SOFCs) are one of the thin film based-solid state ionic devices that can produce electric energy in an eco-friendly way. SOFCs operating at high temperature have the advantages of high cogeneration efficiency and fuel flexibility, but their wide application is limited due to reduced long-term durability and high system cost. Accordingly, many studies have been conducted to develop the thin film-based SOFCs capable of high-performance driving in a low-temperature range.[1,2] Incorporation of nanoscale-thick ceramic electrolytes into SOFCs can minimize energy loss due to slow ion transport in the low-temperature region and achieve high power output.

In this study, we demonstrated the applicability of inkjet printing to the fabrication of thin-film-based SOFCs containing nanoscale-thick yttria-stabilized zirconia (YSZ) electrolyte.[3] Our study was performed using a low-price HP inkjet printer and the structural design of thin film-based SOFC was controlled by the MS Office software. A functional ceramic ink including an electrode and an electrolyte material, respectively, was synthesized to have fluidity suitable for printing. A full inkjet-printed SOFC with nanoscale-thick YSZ electrolyte achieved a peak power density of 730 mw/cm2 at 650°C and a robust durability of 0.0002V h-1. It is significant in that economic feasibility and long-term stability are increasingly emerging as important attributes in terms of generalization of SOFC technology.

References

[1] M. Cassir, A. Ringuedé, L. Niinistö, J. Mater. Chem.
2010, 20, 8987.

[2] J. H. Shim, G. D. Han, H. J. Choi, Y. Kim, S. Xu, J. An, Y. B. Kim, T. Graf, T. D. Schladt, T. M. Gür, F. B. Prinz, Int. J. Precis. Eng. Manuf. - Green Technol.
2019, 6, 629.

[3] G. D. Han, K. Bae, E. H. Kang, H. J. Choi, J. H. Shim, ACS Energy Lett.
2020, 5, 1586.
Evaluation of La2Ce2O7 (LCO) Protection Layer for Proton Conducting Electrolyte
Authors: Fung Kuan-Zong , Tsai Shu-Yi
Published: November 2022

Due to the susceptible reaction BaCeO3-based proton-conductors toward steam and carbon dioxide, La2Ce2O7(LCO) is proposed as a protect layer on top of solid electrolyte since LCO has shown high proton conductivity with adequate stability against steam. In the study, La(NO3)3·6H₂O and Ce(NO3)3·6H₂O were used as precursors to obtain La2Ce2O7(LCO). Particle size analyzer and XRD are applied to analysis this result. From the XRD analysis, it can be seen at the temperature range above 900°C, the reflections representing fluorite-structured LCO appeared with other reflections from BaCe0.5Zr0.3Y0.2O3-δ(BCZY) perovskite substrate. The result can also demonstrate that there is no reaction between LCO layer and BCZY substrate. It is suggested that LCO exhibits good chemical compatibility with BCZY. This synergic bilayer electrolyte design may be a feasible design to overcome the instability of Zr- or Ce-rich Ba(CeZr)O3−δ electrolysis cells against steam and CO2 for better long-term performance. The stability and protection of La2Ce2O7(LCO) on BaCe0.5Zr0.3Y0.2O3-δ(BCZY) will be evaluated based on structural and electrical properties measurement under humid and CO2 containing environment as function of time and temperatures.
Metal-Coordinated Hydrogels As Efficient Oxygen Evolution Electrocatalysts
Authors: Tang Chaoyun , Asefa Tewodros , Wu Nianqiang
Published: November 2022

Conductive polymer hydrogels have large surface area and high conductivity. Their properties can easily be tailored further by functionalizing them with metals and nonmetals. However, the potential of metal-conjugated hydrogels for electrocatalysis has rarely been investigated. In this work, we report the synthesis of transition metals-conjugated polyaniline-phytic acid (PANI-PA) hydrogels that show efficient electrocatalytic properties for the oxygen evolution reaction (OER). Among many transition metals studied, Fe is accommodated by the hydrogel the most because of the favorable affinity of the PA groups in the hydrogel for Fe. Meanwhile, those containing both Fe and Co are found to be the most effective for electrocatalysis of OER. The most optimized such hydrogel, NF@Hgel-Fe0.3Co0.1, which has 3:1 ratio of Fe and Co, needs an overpotential of only 280 mV to catalyze OER with a current density of 10 mV cm-2 in 1 M KOH solution. Furthermore, these metal-doped PANI-PA hydrogels can easily be loaded on nickel foam and carbon cloth via a simple soak-and-dry method to form free-standing electrodes. Overall, the work demonstrates a facile synthesis and fabrication of sustainable OER electrocatalysts and electrodes that are composed of easily processable hydrogels conjugated with various earth-abundant transition metals.

Figure R. Schematic illustration of the synthesis of PA-PANI-Metal (Hgel-M
x
) hydrogels for electrocatalysis of OER.

Figure 1
(Invited) Monolithic All-Perovskite Tandem Cells for Unassisted Water Splitting
Authors: Song Zhaonng , Li Chongwen , Chen Lei , Yan Yanfa
Published: November 2022

The past decade has witnessed a rapid evolution of research on metal halide perovskite-based optoelectronic and energy devices. In light of this remarkable progress, photoelectrochemical (PEC) cells based on halide perovskite photoabsorbers have recently emerged as a promising solar fuel technology. Notably, the bandgap tunability and low-temperature processing make monolithic all-perovskite tandem cells ideal candidates for achieving efficient, cost-effective, unassisted solar-driven water electrolysis devices.

Here, we report our progress on fabricating monolithic all-perovskite tandem cells consisting of two solution-processed perovskite subcells for unassisted water-splitting applications. The all-perovskite tandem devices are achieved by monolithically integrating a wide-bandgap (1.7 – 2.1 eV) Pb-based mixed-halide (Br-I) perovskite top subcell and a narrower-bandgap (1.25 - 1.55 eV) bottom subcell based on Pb-based or mixed Pb-Sn iodide perovskites. Varying the halide perovskite composition for each subcell enables us to tailor the photovoltaic performance of the tandem devices. We demonstrate that all-perovskite tandem devices with various bandgap compositions can deliver open-circuit voltages of more than 2 V. The high photovoltage provides a sufficient overpotential to drive unassisted PEC water splitting with a solar-to-hydrogen conversion efficiency of more than 10%. Additionally, we show that proper water-impermeable encapsulants are needed to prevent degradation of the halide perovskite absorbers in an aqueous environment and enable a long operational lifetime.
(Invited) Towards Broadband Solar Fuel Production
Authors: Ma Dongling
Published: November 2022

Combining nanomaterials of different properties into nanohybrids can potentially lead to improved properties/performance or multiple functions. In particular, forming nanomaterials junctions and using plasmons represent two important, promising strategies for realizing broadband photocalysis in strategically important applications such as solar fuels and photocatalytic degradation of pollutants in our environments. In this talk, I will present some of our recent work on the rational design and realization of nanohybrid materials as well as their applications in solar fuel and photocatalysis. For instance, the construction of homojunctions of nanoplates made of metal–organic frameworks (MOF) led to broadened light absorption and increased photoactivity. The well-defined MOF homojunction was prepared by a facile one-pot synthesis route directed by hollow transition metal nanoparticles. The homojunction is enabled by two concentric stacked nanoplates with slightly different crystal phases. The enhanced charge separation in the homojunction was visualized by in-situ surface photovoltage microscopy. The as-prepared nanostacks displayed a visible-light-driven carbon dioxide reduction with very high carbon monooxide selectivity, and excellent stability. Another example is about the in situ synthesis of plasmonic Ag nanoparticles (AgNPs) and Ag-MOM (metal organic matrix) using one-step facile approach. The intimate and stable interface between the AgNPs and Ag-MOM and hot electron transfer from the plasmonic AgNPs to MOM led to highly efficient visible-light photocatalytic H2 generation in aqueous solution, which surpasses most of reported MOF-based photocatalytic systems. This work sheds light on effective electronic and energy bridging between plasmonic NPs and metal organic matrix.

Related References: [1] Nature communications, 12, Article number: 1231 (2021); [2] Nature communications, 2022, under revision; [3] Chemistry of Materials, 2021, 33, 695-705; [4] Adv. Funct. Mater. 2019, 1902486.
(Invited) Porous Crystalline Materials As Light Absorption and Charge Separation Materials for Solar Fuel Conversion
Authors: Huang Jier
Published: November 2022

Porous crystalline materials such as metal organic frameworks (MOFs) and covalent organic frameworks (COFs) represent a novel class of materials for catalysis due to their inherent porous nature, exceptional thermal and chemical stability, structural flexibility. While many photocatalytic systems based on these materials have been developed in the past decade, a significant gap exists in our understanding of the correlation of photophysical and photocatalytic properties of MOFs/COFs with their structure, which hinders accurate prediction and informed design. We aim to address this challenge using an interdisciplinary approach that combines innovative material design and synthesis, fundamental mechanistic studies, theoretical prediction, and photocatalytic performance evaluation. In this talk, I will discuss our recent progress in developing porous crystalline materials as intrinsic light harvesting materials and heterogenous catalysts for solar fuel generation.
(Invited) Beyond Plasmonic Effect of Metal Nanoparticles in Photocatalysis and Electrocatalysis
Authors: Wu Nianqiang
Published: November 2022

Metal nanoparticles such as gold, silver and copper, exhibit localized surface plasmon resonance effect. The plasmon-enhanced photocatalysis and electrocatalysis of metal nanoparticles receive increasing attention. In addition, metal nanoparticles show other significant effects beyond the plasmonic effect. This talk will discuss and separate other effects of metal nanoparticles from the plasmonic effect.
(Invited) Extracting Photoelectrochemical Phenomena from Transient X-Ray Experiments
Authors: Cushing Scott
Published: November 2022

To date, ultrafast X-ray spectroscopy has been used to measure electron and hole energies, mid-gap state recombination, small polaron formation, and transport of carriers in multi-layer junctions – explaining its appeal for studying photocatalysis and photoelectrochemistry. While ultrafast x-ray spectroscopy can measure both structural and electronic dynamics, the resulting transient plots are complex and hard to interpret because of how photoexcitation perturbs the core-level transition. We will discuss progress in theory and experiment that now allows routine interpretation of photoexcited X-ray edges using a customized DFT-GW-Bethe Salpeter Equation approach. In addition to interpreting excited state phenomenon, the code can project the X-ray peak structure and the relevant X-ray Hamiltonian components - such as angular momentum coupling, screening, and state-filling – onto the band structure to help give physical intuition as to why the measured spectra appear the way they do. The talk will cover the general principles of how photoexcitation modifies transient X-ray spectra rather than detailed theory. Example experiments will include photoelectrodes ranging from ZnTe to complex transition metal oxides.
Impact of Amorphous MnOx Nano-Fibrous Globe-like Structures Towards Photoelectrochemical Water Splitting Properties of Fe2O3 Photoanodes
Authors: Rohilla Jyoti , Gahlawat Soniya , Wang Chien-Yi , Hsu Yung-Jung , Ingole Pravin p
Published: November 2022

Hematite (Fe2O3) is a promising photoanode towards photoelectrochemical (PEC) water oxidation, but its efficiency is hampered by low conductivity and slow surface kinetics. To overcome this, we successfully explored the surface modification of Fe2O3 photoanodes with the electrodeposited amorphous MnOx co-catalyst having unique nano-fibrous globe-like morphology. MnOx overcoated Fe2O3 with optimized MnOx thickness demonstrates the enhanced efficiency towards PEC water splitting, showing four-fold enhancement in its photocurrent density as compared to bare Fe2O3 thin films. Various physico chemical and electrochemical characterizations were conducted to unravel the role of amorphous MnOx co-catalyst over Fe2O3 surface. Results suggest that this enhancement is mainly due to four important factors: (i) An increase in ECSA due to the nano-fibrous morphology of MnOx over layers, (ii) the growth of amorphous MnOx resulting in an increased number of electro-catalytically active centers, (iii) the formation of p-n junction (between p-type MnOx and n-type Fe2O3) at the interface that reduces interfacial charge transfer resistance, and (iv) the presence of Mn with multiple oxidation states, viz. Mn3+ and Mn4+, in MnOx that plays a significant role in water oxidation reaction. We believe that the presented methodology would be helpful for modifying other semiconductors’ surfaces (particularly with n-type conductivity) with amorphous p-type MnOx nanofibrous structures for enhanced PEC water splitting activities.

Keywords: Photoelectrochemical (PEC) water splitting, Hematite (Fe2O3), MnOx amorphous co-catalyst, shunting effect, nano-fibrous morphology.
Optimization of Ascorbic Acid Contents in Preparation of Cobalt Oxide for Highest Oxygen Evolution Activity
Authors: Raitani Kartik , Maurya Manu Prakash , Rajan Hari Krishna , Manjunatha C , Rastogi Chandresh , Maurya Gyanprakash Devendranath
Published: November 2022

The activity of the cobalt oxide (Co3O4) material towards the oxygen evolution reaction is governed by cobalt oxidation states present at the surface. The fabrication methodology decides the concentration of Co+2 and Co+3 at the Co3O4 surface. We used ascorbic acid as a fuel (reductant) for cobalt oxide synthesis. On the variation of the precursor ratio (cobalt nitrate to ascorbic acid) 1:0.5, 1:1, 1:2, and 1:4, the Co+3 and Co+2 content at the surface increases and decreases, while the oxygen vacancy decreases with increasing the ascorbic acid content. The combined effect of oxygen vacancy with Co+2 and Co+3 contents shows the maxima activity for 1:1 sample. Further, low oxygen vacancy with moderate Co+2 and Co+3 contents show low activity compared to the 1:1 sample. Also, high oxygen vacancy with low Co+2 and Co+3 contents show low activity compared to the 1:1 sample. Thus, high Co+2 and Co+3 contents with moderate oxygen vacancy give the highest activity towards the oxygen evolution reaction. The Tafel analysis further supports the above with the help of the Tafel slope. The Tafel slope of the 1:1 sample shows 55.12 mV/dec. Finally, the impedance analysis supports the above by showing the lowest value for the adsorption resistance of the 1:1 sample. Thus, the above study showed that at the ascorbic acid's optimized value, the cobalt oxide showed the highest activity via the moderate oxygen vacancy and highest Co+2 and Co+3 content.
(Invited) Using Ionic Liquid and Organic Salt Additives to Modify CO2 Electroreduction Selectivity on Copper
Authors: Biddinger Elizabeth J. , Sharifi Golru Samaneh
Published: November 2022

Copper is the only metal that can be used as an electrocatalyst to produce hydrocarbons and alcohols in CO2 electroreduction. Controlling selectivity to specific products is very challenging, limiting the viability of CO2 electroreduction on copper to synthesize fuels or chemicals. To obtain products that contain hydrogen, aqueous electrolytes are generally necessary, which also leads to competition with hydrogen evolution reaction (HER). By using ionic additives such as organic salts and ionic liquids, the water and CO2 concentrations at the interface during CO2 electroreduction can be modified. By changing the species at the electrode interface, the product selectivity can be modified. We have found when using dilute concentrations of additives that the anion has more influence on product selectivity. For example, when 10 mM of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTF2] or 10 mM of Na[NTf2] is used in 0.1M KHO3, the product selectivities are very similar, promoting formate formation. When 1-butyl-3-methylimidazolium dicyanamide [BMIM][DCA] or 10 mM of Na[DCA] is used in 0.1M KHO3, CO2 electroreduction is substantially suppressed and HER is promoted. The hydrophobic and CO2-phillic [NTf2] likely limits the water available at the surface while increasing the concentration of CO2. The hydrophilic and CO2-phobic [DCA] likely increases the water available at the surface and diminishes the concentration of CO2 available for reaction.
Electrochemical CO2 Conversion with Packed Bed Membraneless Electrolyzers
Authors: Pang Xueqi , Verma Sumit , Liu Chao , Esposito Daniel V.
Published: November 2022

(Bi)carbonate electrolysis offers an attractive opportunity for integrated carbon dioxide (CO2) capture and conversion whereby a carbonate-laden aqueous capture solution can be directly fed to an electrolyzer before being recycled to the CO2 capture unit(s). Among the previous studies that have demonstrated the viability of (bi)carbonate electrolysis, bipolar membranes are commonly used to deliver protons to the cathode where they convert (bi)carbonate into CO2 that is subsequently reduced at the cathode. However, these membranes can be susceptible to fouling or degradation, which may lead to device failure. Here, we present a scalable and potentially low-cost packed bed membraneless electrolyzer (PBME) concept for the conversion of bicarbonate into CO based on train of porous flow-through electrodes. At the anode, hydrogen oxidation reaction is used to produce protons, which rapidly react with bicarbonate to generate CO2 for electrochemical CO2 reduction at the downstream cathode in this membrane-free electrolyzer design. This study highlights the ability of the PBME design to minimize the magnitude of pH swings within the electrolyzer and enable high CO2 utilization rates. Tests of multi-cell PBMEs show enhanced performance compared to single-cell PBMEs and demonstrate the scalability of this PBME design.