bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Photoelectrode Design for Photoelectrocatalytic Hydrogen Production
Authors: Wang Lianzhou 
Published: August 2024

Semiconductor nanomaterials hold the keys for efficient solar energy harvesting and conversion processes like photocatalysis and photoelectrochemical reactions. In this talk, we will give a brief overview of our recent progress in designing semiconductor nanomaterials for photoelectrochemical energy conversion including solar hydrogen generation and low-cost solar cells. In more details, we have been focusing on a few aspects; 1) photocatalysis mechanism, light harvesting, charge separation and transfer and surface reaction engineering of low-cost metal oxide based semiconductors including TiO2, BiVO4 as efficient photoelectrode for photoelectrochemical hydrogen production; 2). The design of ultra-stable composites of perovskite-MOF with improved light emitting and photocatalytic performance.1-5 The resultant material systems exhibited efficient photocatalytic performance and improved power conversion efficiency in solar cells, which underpin sustainable development of solar-energy conversion application.

References
：

1. Adv. Mater., 2018, doi:10.1002/adma.201705666.
2. Angew. Chem, 2019, doi/10.1002/anie.201810583
3. Nature Commun, 2020, (2020) 11:2129
4. Science, 2021, 374, 621.
5. Adv. Mater., 2022, 34 (10), 2106776.
(Invited) Design Rules for (Li-mediated) Photoelectrochemical N2 Reduction to NH3
Authors: Nielander Adam C. 
Published: August 2024

The electrochemically-driven N2 reduction reaction (N2RR) offers an alternative route to the traditional Haber-Bosch method for production of NH3. Electrifying NH3 synthesis promises a route to the decarbonization and decentralization of ammonia production, which currently accounts for >1% of annual CO2 emissions. While there have been many studies examining electrochemically-driven production of NH3 in aqueous electrolytes at low-T (≤ 50o C) and low-P (≤20 bar), lithium-mediated N2 reduction (Li-N2R) in nonaqueous electrolytes at low-T and low-P has emerged as a promising method for obtaining reliable electroreduction of N2 to NH3.
With this in mind, our team at SUNCAT and NREL have begun evaluating the opportunity and key design rules necessary for coupling photoelectrochemical methods to the drive the Li-N2R reaction using solar illumination. Nonaqueous, photoelectrochemical Li-N2R promises a route to stable operation that has been a key challenge associated with photoelectrode operation in aqueous electrolytes. Recognizing the energetic constraints associated with the Li-mediated process, we have modeled and mapped the bandgap characteristics necessary for a semiconducting light absorber to drive the Li-N2R reaction and the maximum attainable solar-to-NH3 conversion yields. We have identified III-V based photoelectrodes that meet the modeled requirements and evaluated the surface chemistry at the electrode/electrolyte interface under Li-N2R conditions to understand the how reactive Li-species influence photoelectrochemical performance (e.g., rate, selectivity, stability), how solid-electrolyte interface (SEI) formation and electrolyte selection are mutually influenced by illumination, and how the current density and cycling conditions enforced by solar operation dictate photoelectrochemical N2-to-NH3 performance. We have further extended a neutron-reflectometry technique used for in situ observation of interfacial layer formation to be compatible with light-driven reactions, and with these insights in hand continue our drive toward demonstrating unassisted photoelectrochemical N2-to-NH3 production.
Investigation of Cu-Oxidation and Its Roles in Unassisted CO2 Reduction and Electrochemical Oxygen Evolution
Authors: Basera Pooja , Zoric Marija , Zhao Yang , Boettcher Shannon W. , Codones-Hahn Amy , Bajdich Michal 
Published: August 2024

Sunlight-driven photocatalytic CO2 reduction to CO under unassisted (unbiased) conditions was recently demonstrated using heterostructured catalysts that combine p-type GaN with plasmonic Au nanoparticles and Cu nanoparticle co-catalysts (p-GaN/Al2O3/Au/Cu) [1]. However, the exact oxidation state of Cu and the hole transfer directionality between Au and Cu remain under debate. Here, we combine computational and experimental efforts to investigate the different oxidation states of Cu under unassisted photocatalytic operating conditions. Experimentally we found that the Cu nanoparticles are primarily composed of Cu2O and CuO, CuCO3.Cu(OH)2 species, with no detectable metallic Cu present. The calculated bulk thermodynamics confirmed the high stability of CuCO3.Cu(OH)2 which is also validated by its largest contribution in the Pourbaix diagram, consistent with experimental observations. To gain insights into the origin of charge transfer, we simulate material interfaces namely, Au/CuO, Au/Cu2O, and Au/CuCO3.Cu(OH)2. Our theoretical analysis supports experimentally observed light-driven hole transfer from Au to Cu.
More recently significant progress has been made in understanding copper oxide (CuO) behavior at oxidizing electrochemical conditions (> 1.5 V) [2]. In our study, we show CuO transforms into the OER active phase CuOOH, as evident in the bulk Pourbaix diagram presented here. Our calculations show a novel square planar, non-magnetic CuOOH phase. This discovery is supported by calculated Raman spectroscopic analysis, revealing distinct features corresponding to Cu3+ species at 567 and 585 cm-1, closely matching experimental peaks at 587 cm-1. These findings provide insights into the electrochemical properties of copper oxide phases and their relevance towards electrocatalytic OER.

Acknowledgments:
This material is based on work performed by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Fuels from Sunlight Hub under Award Number DE-SC0021266.

Reference:
[1] H. A. Atwater et al. ACS Energy Lett, 6, 1849 (2021)
[2] M J. Janik et al. ACS Appl. Mater. Interfaces, 15, 27878 (2023)
(Invited) Unraveling Hot Carrier Transfer Processes in Plasmonic Catalysis
Authors: Tagliabue Giulia 
Published: August 2024

In the last decade, plasmonic nanoantennas have revolutionized light manipulation and control at the nanoscale. Interestingly, generation of hot carriers in metals upon light absorption have opened new pathways for controlling photo(electro)chemical processes and engineering photocatalysts. Yet, fundamental questions remain about the microscopic details of these complex light-matter interactions.
We have recently developed a well-controlled platform for micro-scale plasmonic photoelectrochemistry studies that leverages the unique properties of monocrystalline microflakes [1] as well as precise nanofabrication methods. Interestingly, the microflakes exhibit well-defined crystal facets and can bridge the properties of bulk metals with those of nanoscale plasmonic antennas, accessing ultra-thin film dimensions (sub 15-nm) that are challenging for polycrystalline films. By performing careful absorption measurements, we explore the photoelectrochemical performance of these hot carrier micro-scale photoelectrodes for inner- and outer-sphere reactions [2], concurrently comparing them to cm-scale devices [3]. This allows us to unravel the interplay of hot carrier generation and transport at metal-liquid and metal-semiconductor interfaces and identify bottlenecks for charge transfer.
[1] Kiani F., Tagliabue G. - High‐Aspect Ratio Au Microflakes via Gap‐Assisted Synthesis – Chemistry of Materials 34 (3), 1278-1288, 2022
[2] Kiani F. et al - Transport and Interfacial Injection of d-band Hot Holes Control Plasmonic Chemistry - ACS Energy Letters, 8 (10), 4242-4250, 2023
[3] Ma J., Oh K., Tagliabue G. - Understanding Wavelength-Dependent Synergies between Morphology and Photonic Design in TiO2-Based Solar Powered Redox Cells – Journal of Physical Chemistry C, 127 (1), 11-21, 2022
(Invited) Techno-Economics of Photoelectrochemical Water Splitting and Progress in Cost Reduction of High-Efficiency III-V Photoabsorbers
Authors: Deutsch Todd G , Wyatt Keenan , Young James L. , Steiner Myles A. 
Published: August 2024

Photoelectrochemical (PEC) water splitting is a potentially promising route to direct solar-driven hydrogen production. Challenging targets for solar-to-hydrogen (STH) efficiency, durability, and semiconductor absorber costs must be realized for this approach to be economically competitive with other hydrogen production pathways. The first part of this talk will focus on the cost and performance metrics that go into techno-economic analysis and their status.
Research on PEC hydrogen production at the National Renewable Energy Laboratory (NREL) has focused on III-V semiconductor absorber materials because their tunable bandgaps, high photon conversion efficiencies, and ability to make multi-junction structures that have resulted in the highest STH efficiencies yet demonstrated. However, to achieve the U.S. DOE’s hydrogen production target of $2/kg, in addition to high STH efficiency, the semiconductor absorber synthesis cost must come down 1-2 orders of magnitude from the current metal organic vapor phase epitaxial route. Hydride vapor phase epitaxy (HVPE) is a technique that has the potential to lower tandem III-V synthesis costs. The second part of this talk will describe experimental photoelectrochemical characterizations of HVPE-grown GaInP/GaAs tandem photoelectrodes with 1.85/1.38 eV bandgaps. Their incident photon-to-current efficiency, photocurrent vs. circuit bias, and unbiased chronoamperometry will be presented and discussed. Upon illumination, the HVPE-grown structures were able to drive water electrolysis spontaneously (e.g., without an external bias) at STH efficiencies up to 10%. The durability of III-V photoelectrodes remains an unresolved challenge for cost effective hydrogen production via photoelectrolysis.
(Invited) Innovating Sustainable, Cost-Effective, and Durable Redox Flow Battery Membranes
Authors: Yang Guang , Lehmann Michelle , Self Ethan , Saito Tomonori 
Published: August 2024

In the quest to integrate renewable energy sources like solar and wind into the electric grid efficiently, the development of long-duration energy storage (LDES) systems is paramount. The U.S. Department of Energy's Long Duration Storage Shot initiative is at the forefront of this endeavor, aiming to reduce the costs of grid-scale energy storage by 90% for systems with over 10 hours of operation. A key player in this mission is the non-aqueous redox flow battery (RFB), known for its use of earth-abundant materials and potential to meet these cost-reduction goals. However, the commercial viability of RFBs hinges on the development of high-performance, cost-effective membranes, which are crucial for their functionality and affordability. These membranes' ionic conductivity is vital for the power density of RFBs, while their ion selectivity and solvent uptake greatly influence the batteries' cycle life.
Our team has made groundbreaking advancements in membrane technology for non-aqueous flow batteries. We've addressed the challenge of balancing ionic conductivity with mechanical strength in polymer electrolytes. Our findings reveal that enhanced solvent uptake while boosting membrane ionic conductivity, can compromise mechanical integrity. To counter this, we've employed two strategies: selective plasticization of the ion-conductive block in block copolymers and reinforcing the membrane's mechanical strength through hydrogen and ionic bonds with an inorganic scaffold. Significantly, we've also reduced the crossover of redox-active species in our membrane designs, notably decreasing polysulfide species crossover in a Na metal – polysulfide hybrid flow battery. This has led to improved capacity retention, Coulombic efficiency, and extended cycle life compared to traditional porous membranes.
Our latest innovations include the development of hydrocarbon single-ion conductors, demonstrating enhanced conductivity and stability. We've also introduced crosslinking chemistry to control solvent uptake more effectively, thus improving ionic conductivity while preserving mechanical strength. Lastly, our pioneering tape casting method for producing ceramic-polymer composite membranes represents a major leap in scalable membrane production, paving the way for the practical application of non-aqueous redox flow batteries in long-duration energy storage.

Acknowledgment

This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is sponsored by the U.S. Department of Energy through the Energy Storage Program in the Office of Electricity. We acknowledge Dr. Jagjit Nanda SLAC National Accelerator Laboratory for the fruitful discussions.
(Invited) Unlocking Long-Duration Energy Storage with Unitized Reversible Fuel Cells
Authors: Komini Babu Siddharth , Arman Tanvir Alam , Li Yuanchao , Li Kui , Diaz-Abad Sergio , Murphy Eamonn , Fu Jintao , Liyanage Wipula Priya Rasika , Wang Xiaojing , Spendelow Jacob S. 
Published: August 2024

As the proportion of energy supplied by renewable sources continually rises, the intermittent nature of these sources necessitates efficient energy storage to meet the demand of the grid. Hydrogen is a promising energy carrier for grid-scale storage due to its capacity for months-long storage without energy loss or self-discharge.(1) Reversible fuel cells generate power for the grid in fuel cell (FC) mode during periods when renewable power production is lower than demand, utilizing stored H2 generated by water electrolysis (WE) during periods when renewable power production exceeds demand from the grid. Unitized reversible fuel cells (URFCs) efficiently integrate WE and FC operation in a single electrochemical device, potentially reducing costs and providing higher energy density. In constant gas URFC operational configuration, both the oxygen evolution reaction (OER) for WE and the oxygen reduction reaction (ORR) for FC occur within the same electrode.(2) The contrasting electrode requirements for FC and WE have constrained the round-trip efficiency (RTE) of URFCs, highlighting the crucial need to improve RTE for greater competitiveness and widespread commercial adoption.
This presentation will discuss the results from development of novel bifunctional catalysts, electrode architectures, and porous transport layers (PTLs) aimed at enhancing efficiency and durability of URFCs. This talk will present the development of bifunctional catalysts and their supports to boost OER and ORR performance. Additionally, we will present insights into innovative electrode architecture designed for optimal utilization of the catalysts, thereby maximizing efficiency. The development of specialized PTLs featuring amphiphilic wettability and intricately engineered microporous layers will be presented emphasizing their role in increasing the performance and durability of URFCs.

Acknowledgement

This research is supported by the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory (LANL) under project 20240061DR, and by the U.S. Department of Energy Hydrogen and Fuel Cell Technologies Office (DOE-HFTO) with support from technology manager Donna Ho.

References

Hydrogen Council, Hydrogen scaling up: a sustainable pathway for the global energy transition, in (2017).

S. Komini Babu et al., Advanced Energy Materials, 13, 2203952 (2023).
Exploring Cell Designs for Redox Flow Batteries with Flowable Suspension-Based Electrolytes
Authors: Majji Madhu V. , Brushett Fikile R. 
Published: August 2024

Integrating flowable suspension-based electrolytes (FSEs) in redox flow batteries (RFBs) may expand the materials design space and unlock new pathways to cost-competitive stationary energy storage.1 In this approach, conductive particles are suspended in electrolyte solutions, forming electronically conductive networks that shuttle charge to and from the reaction volume, potentially replacing stationary porous electrode with RFB stacks. This configuration offers several potential benefits including access to extremely high surface areas for charge-transfer reactions, plating/stripping on a mobile solid phase, and the use of insoluble (or sparingly soluble) active species.2 However, FSEs often display shear-dependent properties that impact electrochemical and fluid dynamic performance and challenge compatibility with current electrochemical flow cells which are largely designed to support low-viscosity Newtonian fluids.1,3,4 As such, there is a need to consider alternate cell designs that may be better suited for FSEs.
We recently developed a continuum-based model and investigated how the performance of an RFB cell with an FSE changes as a function of material properties, cell dimensions, and operating conditions.4 In this presentation, we will use this modeling framework to explore three different cell configurations: fixed parallel plates, parallel plates with a linearly moving wall, and rotating concentric cylindrical surfaces. The distinct geometries and operational environments associated with each cell design result in different fluid flow and charge transport profiles which, in turn, alter the performance. We will compare and contrast fluid dynamic and electrochemical features of the three different configurations, with a focus on establishing operating envelopes and identifying which may best support FSEs. Ultimately, we aim to extend the design space considered for RFBs with FSEs as well as to better connect component material properties to cell engineering.

Acknowledgments

This work was supported by bridge funds from the Massachusetts Institute of Technology.

References

F. Savinell, and J. S. Wainright, The Electrochemical Society Interface 32, 61 (2023).

Parant et. al., Carbon, 119, pp.10-20 (2017).

C. Hoyt et. al., Chemical Engineering Science144 (2016): 288-297.

M. V. Majji et. al., Journal of The Electrochemical Society, 170(5), p.050532, (2023).
Potential-Dependent BDAC Adsorption on Zinc Enabling ‘Selective’ Suppression of Zinc Corrosion for Energy Storage Applications
Authors: Phung Theodore , Akolkar Rohan , Sinclair Nicholas Scott 
Published: August 2024

Utility-scale zinc (Zn) batteries are a promising solution to address the problem of intermittency of renewable energy sources[1],[2]; however, Zn-metal anodes in these batteries suffer from capacity loss due to spontaneous corrosion of the Zn especially when high-surface area anode configurations are employed[3]. Additionally, Zn dendrites are known to form during battery charging which limits the cycle-life of these batteries. Electrolyte additives have been explored that prevent the aforementioned issues[4],[5], but these too come at a cost, i.e., surface-blocking additives polarize the electrode surface leading to loss in the voltaic and energy efficiencies of the battery. In this presentation, a novel electrolyte additive, benzyldimethylhexadecylammonium chloride (BDAC), will be presented for its ability to suppresses corrosion of Zn in a mildly acidic (pH = 3) electrolyte. An attribute of BDAC distinct from previously studied additives is that it ‘selectively’ suppresses corrosion when the Zn electrode is held near its mixed potential; however, during high-rate Zn deposition (charging) or stripping (discharging), BDAC is essentially deactivated and thus does not appreciably polarize the electrode surface. This selective corrosion suppression behavior is explored using slow-scan cyclic voltammetry, which reveals a hysteretic response. The response implies a current-dependent BDAC adsorption mechanism in which BDAC reaches higher surface coverages when the partial currents at the Zn surface are low (e.g., at or near the corrosion mixed potential), but BDAC coverage is reduced considerably when the Zn deposition-stripping rates are increased. Numerical simulations of the BDAC diffusion-adsorption process are used to corroborate this model. Ramifications of our approach to the selective suppression of Zn dendrites will also be discussed.

References:

[1] J. Kosowatz, “Energy Storage Smooths the Duck Curve,” Mech. Eng., vol. 140, no. 06, pp. 30–35, Jun. 2018, doi: 10.1115/1.2018-JUN-1.
[2] W. Cole, P. Denholm, V. Carag, and W. Frazier, “The peaking potential of long-duration energy storage in the United States power system,” J. Energy Storage, vol. 62, no. February, p. 106932, 2023, doi: 10.1016/j.est.2023.106932.
[3] C. J. Kellamis and J. S. Wainright, “A zinc–iodine hybrid flow battery with enhanced energy storage capacity,” J. Power Sources, vol. 589, no. July 2023, p. 233753, 2024, doi: 10.1016/j.jpowsour.2023.233753.
[4] J. L. Ortiz-Aparicio, Y. Meas, T. W. Chapman, G. Trejo, R. Ortega, and E. Chainet, “Electrodeposition of zinc in the presence of quaternary ammonium compounds from alkaline chloride bath,” J. Appl. Electrochem., vol. 45, no. 1, pp. 67–78, 2015, doi: 10.1007/s10800-014-0777-9.
[5] F. Mansfeld and S. Gilman, “The Effect of Lead Ions on the Dissolution and Deposition Characteristics of a Zinc Single Crystal in 6 N KOH,” J. Electrochem. Soc., vol. 117, no. 9, p. 1154, 1970, doi: 10.1149/1.2407584.
Energy Storage Capacity Utilization in Redox Flow Batteries
Authors: Bachman Ridge M. , Gamwo Isaac K. , Hall Derek M. 
Published: August 2024

Redox flow batteries (RFBs) are predicted to be a major contributing technology in the need for four-to-ten-hour energy storage. Other energy storage technologies, such as lithium-ion batteries, provide well-documented performance indicators such as efficiency and especially energy storage capacity utilization. While redox flow batteries are compared similarly based on cost and round-trip efficiency, they often neglect a comparison of their operational energy storage capacity utilization. The breakdown of operational losses that represent the current state of operation for RFBs are pivotal to further compare the development of these technologies to the standard of other electrochemical storage devices. Quantifying the current state-of-the-art in relation to the theoretical potential of RFBs allows us to assess the extent of development required to enhance their effectiveness in contributing to future energy storage goals.
In this work, we set out to depict the operational energy storage density (W-h L-1) of various redox flow battery technologies based on consideration from experimental parameters and results from literature as key inputs. After reviewing five RFBs including the all-vanadium RFB, Hydrogen-Bromine RFB, All-Iron RFB, Zinc-Bromine RFB, and the Iron-Chromium RFB, results indicate that the VRFB is the most developed technology attaining around 60% of its theoretical energy storage density. While the Zinc-Bromine RFB has approximately the largest theoretical energy storage density (due to its high electroactive species concentration and standard potential difference), it is currently only able to operate at about a lowly 15% of it, dependent on its operational current density. We also assess the volumetric footprint for each RFB electrolyte system by considering a 6 MWh (6 MW, 1 hr) system. This assessment considers how large the electrolyte component of the RFB would be for operation. The Hydrogen-Bromine RFB would require electrolyte tanks to be more than 1600 m3 based on operational parameters, but if it were able to operate at 100% of its capability, the electrolyte tanks would shrink to be about 400 m3.