bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Recovering from Precipitation Events in Redox Flow Batteries
Authors: Saraidaridis James , Yang Zhiwei , Darling Robert M.
Published: December 2020

Liquid electrolyte solutions containing dissolved active material imbue Redox Flow Batteries (RFBs) with many unique benefits relative to solid-state electrochemical energy storage devices: long shelf-life, long system life-time, de-coupled rated energy and power, ease of recyclability.1 Operating a RFB system with flowing electrolyte solutions presents unique concerns as well, with one notable concern arising from possible precipitation of electrolyte. Precipitation of active material can have many consequences including sensor inaccuracy, inaccessible storage capacity, partially- or fully-blocked reactor electrode regions, and system clogging.

Aqueous vanadium RFBs, a leading chemistry in commercial systems, has a precipitation mechanism at high temperatures for battery solutions containing commercially relevant vanadium concentrations >1.5 M. At elevated temperatures (> 40°C), positive electrolyte solutions can precipitate V2O5 dimers, first as a gel-like substance and eventually as solid particles.2 The Raytheon Technologies Research Center team has developed recovery procedures for systems that may succumb to such precipitation events; in the case for aqueous vanadium RFBs, exposure of precipitate to lower oxidation state forms of vanadium (i.e. negative electrolyte) reduces and redissolves precipitated V2O5. This electrolyte takeover process (ETP) can successfully redissolve precipitates and recover performance from precipitate-induced cell/stack under-performance.

As Raytheon Technologies Research Center pursues alternative low-cost flow chemistries, the same ETP principles are applied to other chemistries such as polysulfide-based systems, known for sulfur crossover and precipitation of elemental sulfur in positive electrode volumes.3 This abstract will discuss the progress made at the Research Center to recover from precipitation events in such chemistries, which, unlike aqueous vanadium, do not permit simple mixing of negative and positive electrolytes.

Acknowledgements:

The authors gratefully acknowledge support from Vionx Energy Corporation. Some of the work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR000994. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

References:

Chalamala, B. R.; Soundappan, T.; Fisher, G. R.; Anstey, M. R.; Viswanathan, V. V.; Perry, M. L., Redox Flow Batteries: An Engineering Perspective. Proceedings of the IEEE
2014,
102 (6), 976-999.

Skyllas‐Kazacos, M.; Menictas, C.; Kazacos, M., Thermal Stability of Concentrated V(V) Electrolytes in the Vanadium Redox Cell. Journal of The Electrochemical Society
1996,
143 (4), L86-L88.

Su, L.; Badel, A. F.; Cao, C.; Hinricher, J. J.; Brushett, F. R., Toward an Inexpensive Aqueous Polysulfide–Polyiodide Redox Flow Battery. Industrial & Engineering Chemistry Research
2017,
56 (35), 9783-9792.
Performance Survey for Li-Ion Battery in a Hybrid Vehicle with 105,000 Km Driving
Authors: Koshika Kenichiroh , Suzuki Hisakazu
Published: December 2020

A global technical regulation for vehicle environmental performance such as exhaust gases, fuel economy and range has appeared in the issue of WP29 in the United Nations Economic Commission for Europe (UN-ECE). [1] One of major concerns is that battery degradation may influence on the fuel economy deterioration of electrified vehicles such as HEVs. However, numbers of report from automakers about the relation between a fuel economy change and battery performance change are limited. In this paper, we demonstrate the battery performance change in a hybrid vehicle with 105,000 km driving and its fuel economy change.

Fuel consumptions of the hybrid vehicle with 1.5 L gasoline engine and 105,000 km driving were compared before and after battery pack replacement. The type of the battery was Lithium-ion. The fuel consumptions with the “state of charge correction” were measured by a chassis dynamometer with Japanese driving test cycle of “JC08 mode” (Fig.1). Before replacing the battery pack, the hybrid vehicle ran with a fuel consumption of 29.24 km/L. Then after replacing the battery ran with a fuel consumption of 29.96 km/L.

After the fuel consumption test, the battery pack with 105,000 km driving was disassembled to battery cells. Discharge capacities and internal resistances of the cells were measured. We will discuss the battery performance change and its influence on the fuel consumption rates of the vehicles.

[1]https://www.unece.org/trans/main/wp29/introduction.html

Figure 1
(Invited) Statistical Distribution and Feasibility for Re-Use of A123 LiFePO4 Cells from a Hybrid-Bus Battery Pack
Authors: Ramirez-Meyers Katrina , Rawn Barry , Whitacre Jay
Published: December 2020

Second-use applications for batteries can play an important role in reducing the environmental impacts and life-cycle costs of electrochemical energy storage. The economic feasibility of re-using a battery pack is strongly influenced by the state-of-health (SOH) of its modules and cells after primary use. Thus, there is a strong incentive to optimize procedures for diagnosing SOH based on parameters such as calendar life, cycle life, internal resistance, and capacity fade. In this paper, we analyze the statistical distribution of the SOH cells extracted from a retired BAE-Systems ESS-A123 hybrid bus battery pack. The pack consists of 16 modules in series, each containing 96 lithium-iron-phosphate 26650 cells in a 12s8p configuration. Most of the modules use ANR26650M1-A (M1-A) cells. Two modules use M1-B cells—a newer version of the same battery—indicating that these two modules were installed as replacements. The M1-A and M1-B cells have nominal capacities of 2.3 and 2.5 Ah, respectively. We randomly sampled one cell from each of the 192 sub-modules that result from the 8p design and performed a comprehensive SOH assessment.

We will summarize the data by presenting internal resistance, discharge capacity, Warburg diffusion coefficient, and charge-transfer resistance as a function of cell location and type. Results show that the M1-A cells display widely varying SOH, while the M1-B cells are in much better condition. The wide range in SOH parameters suggest re-use of all parts of the pack may not be economically reasonable.

We will also present an analysis of the duty profile of the bus battery. We will then discuss the implications of our findings for the economic feasibility of re-using the cells and modules, in light of available data and modeling techniques.
Sensing Elevated Carbon Dioxide Levels for Detecting Battery Cell Venting in Packs
Authors: Cai Ting , Engle Brian , Stefanopoulou Anna G , Siegel Jason B
Published: December 2020

Li-ion battery thermal runaway is a critical safety issue for large-scale battery packs, and gas venting of a battery cell is a precursor of an imminent thermal runaway. The proposed global technical regulation No.20 on Electric Vehicle Safety requires an advance warning 5 minutes prior to hazardous conditions caused by a thermal runaway event. Voltage-based detection methods are less effective in large packs with many parallel connected cells, and temperature-based methods provide slow and sparse information when fewer than 10% of the cells are instrumented. To achieve immediate detection for thermal runaway, vent-gas detection methods are promising due to their fast response and easy implementation in a pack. The composition of battery vent-gas during faults that can lead to a thermal runaway event include CO2, CO, H2, and volatile organic compounds (VOCs). The best gas species to target for a detection strategy is still debated. The composition of the vent-gas depends on cell chemistry, abuse condition, and cell state of charge. For robustness, the detection strategy needs to be sensitive to all possible failure mechanisms, be inexpensive, and require no maintenance. A Non-Dispersive Infrared (NDIR) CO2 sensor can meet these requirements, because the detection can be made immediately when the presence of CO2 is observed from the first venting event, and the sensor type has low cost and with some sensor’s lifetime over 15 years.

To check the NDIR sensor responsiveness, an overcharging test for a prismatic 4.9 Ah cell was performed and the gas venting is observed before thermal runaway is triggered. Quickly after the occurrence of gas venting, the NDIR CO2 sensor showed a strong response with maximum gas concentration exceeding 30,000 ppm as shown in the figure. In a battery pack, the fast velocity of the ejected gas from cell venting ensured the fast response of the gas sensor. To apply the gas detection strategies for large battery packs, the volume and average CO2 concentration can be modeled to set the gas detection threshold.

Figure 1
Robust Performance and Safety Advantages of Large Cells for Energy Storage Based on HE3DA (3D) Electrode Concept - from a Lab Sample to a Gigafactory
Authors: Prochazka Jan , Zukalova Marketa
Published: December 2020

The HE3DA® concept of several millimeters thick electrodes (3D) gives the lithium battery incomparable safety and brings a number of new technical attributes, which are not achievable by the existing thin film technology (2D).

The safe and robust construction with multifunctional frames, easy degassing, low internal resistance and electrolyte regeneration make this new lithium accumulator technology ideal for high capacity batteries and large energy storage modules, optionally with an internal cooling system, which radically shrinks the battery pack size and extends the battery life.

The 3D construction of HE3DA technology provides an efficient thermal management and inherited safety to the batteries, enabling construction of very large cells on hundred KWh level and modules on hundreds of MWh scale. Incomparable safety, cheap manufacturing process and performance robustness make this technology ideal for the Smart Grid applications, stabilizing solar and wind power generation, changing this type of renewable energy from unpredictable to predictable. HE3DA technology platform has been developed from a lab sample into a mass scale production on Gigawatt hour scale in the past 10 years.

Typical performance data will be introduced.

Figure 1
Cost and Economic Analysis of a Polymer Sealed Planar Na-NiCl2 Battery for ESS
Authors: Lee Jung Seung , Yang Choongmo , Jung Keeyoung
Published: December 2020

In order to commercialize the battery-based ESS, it is necessary to consider not only the technical characteristics of stability and long life, but also the economic characteristics of manufacturing cost. This study aims to analyze the manufacturing cost of a polymer sealed planar Na-NiCl2 battery that is currently being researched and developed for safe, long life and untra low cost energy storage and to predict economic efficiency.

Manufacturing cost analysis was calculated by dividing a number of technically feasible alternatives for each layer of cells, modules, packages, and applications into fixed, variable, and indirect costs. The economic feasibility analysis calculated the cost-benefit ratio by comparing the cost of the next 10 years and the purchase price and purchase plan of the ESS consumer derived from the manufacturing cost analysis. Data required for manufacturing cost analysis and economic analysis include public data such as power consumption patterns and weather data, as well as internal data from research and development institutions such as material and processing costs, as well as external data from suppliers, consumers and competitors. This study obtained relevant data by intensively interviewing the research and development personnel of Na-NiCl2 battery and the stakeholders located in the supply chain of this battery, and utilized secondary data already processed and published, such as the London Metal Exchange and the Statistics Korea.

As a result of analysis, we found that the proposed ESS based on a polymer sealed planar Na-NiCl2 battery has a comparative advantage economically compared to the competitive LiB-based ESS and ZEBRA ESS. Looking at the results of this study, we expect to be able to commercialize safe, long life and untra low cost energy storage in the near future.
Dissolution Stability of Photoanodes and Co-Catalysts in Photoelectrochemical Water Splitting
Authors: Knöppel Julius , Kormanyos Attila , Mayerhöfer Britta , Hofer André , Speck Florian Dominik , Bachmann Julien , Thiele Simon , Cherevko Serhiy
Published: December 2020

In the future energy scenario, production of hydrogen is a promising solution for the storage of renewables.

Photoelectrochemical water splitting with integrated devices can be engaged for the production of hydrogen with the

advantage of less space consumption and saving power lines to the production site. Current devices have already

come close to the efficiency of an electrolyzer coupled to a solar cell [1]. However, to be profitable in commercial use

several challenges have to be resolved. One of the most pressing issues is photostability of materials during operation.

Even so photoelectrodes are able to reach lifetimes of several days in lab conditions, it is still a long way until real

device lifespans of several years are possible.

While efforts in the field of photoelectrochemical water splitting is mainly focused on achieving higher activity, research

on stability is still at the very beginning. Evaluation of photostability is typically done by rather short (only few hours)

chronoamperometry measurements and post mortem analysis. One option to study degradation processes in-situ is to

use on-line inductively coupled plasma mass spectrometry (on-line ICP-MS) which became available recently and

revealed photocorrosion of WO3 [2] and BiVO4 [3].

In this study, we aim to achieve a better understanding of the key factors driving photocorrosion. It has already been

shown, that WO3 exhibits significant differences in faradaic efficiency towards the oxygen evolution reaction (OER) in

various electrolytes [4]. One reason behind this behavior might be degradation processes driven by the electrolyte. To

study the effect of electrolytes on stability, dissolution of spray-coated WO3 films was investigated in four electrolytes

(HClO4, H2SO4, HNO3 and CH3SO3H). Additionally, the influence of protective iridium co-catalyst layers on stability,

synthesized in various thicknesses by atomic layer deposition (ALD) was explored.

1. Cheng, W.-H., et al., Monolithic Photoelectrochemical Device for Direct Water Splitting with 19% Efficiency. ACS

Energy Letters, 2018. 3(8): p. 1795-1800.

2. Knöppel, J., et al., Time-resolved analysis of dissolution phenomena in photoelectrochemistry – A case study of

WO3 photocorrosion. Electrochemistry Communications, 2018. 96: p. 53-56.

3. Zhang, S., et al., Dissolution of BiVO4 Photoanodes Revealed by Time-Resolved Measurements Under

Photoelectrochemical Conditions. The Journal of Physical Chemistry C, 2019.

4. Reinhard, S., F. Rechberger, and M. Niederberger, Commercially Available WO3 Nanopowders for

Photoelectrochemical Water Splitting: Photocurrent versus Oxygen Evolution. ChemPlusChem, 2016. 81: p.

935-940.
(Invited) Photoelectrochemical Syntheses of H2O2 Via O2 Reduction Using p-Type CuBi2O4 or Cu3VS4 Electrode Under Visible Light
Authors: Ohno Teruhisa , Tanaka Tomoyuki , Teng Zhenyuan
Published: December 2020

Hydrogen peroxide (H2O2) is a promising solar fuel with advantages of easy storage and high energy density. Here, we report in situ photoelectrochemical synthesis of H2O2 via O2 reduction reaction (ORR) using a p-type CuBi2O4 (CBO) electrode at an applied voltage far lower than the theoretical electrolysis voltage under visible light irradiation. Although a CBO electrode has a major limitation for PEC devices due to redox instability in aqueous solution, it exhibits an unexpected, surprisingly high H2O2 activity in the presence of O2 without having a deleterious impact on the durability of the electrode. We also reported about the fabrication of a new p-type Cu3VS4 electrode for H2O2 production under visible light irradiation.

Figure 1
(Invited) Nanostructured Photoelectrochemical Electrodes and Electrocatalysts for Efficient Solar Energy Conversion
Authors: Yang Shihe
Published: December 2020

Photoelectrochemical (PEC) water splitting is a promising technique to directly convert solar energy into hydrogen energy for storage and transportation. PEC devices need to efficiently absorb sunlight and separate and collect the photocarriers. Herein we will present our recent work on the development of photonic structures for light trapping, PEC electrodes and electrocatalysts for water splitting. The importance of understanding both the light harvesting and the charge collection characteristics will be highlighted for the light trapping structural design. For electrocatalysts, we will focus on two-dimensional (2D) materials, and combine experimental and theoretical techniques to reveal the importance of the specific nanostructures for hydrogen evolution reaction and oxygen evolution reaction in electrolytes of different pH values. Our overall goal is to develop cost-efficient and robust photocatalysts and electrocatalyst to efficiently convert the abundant solar energy to clean, storable and transportable chemical fuels.
(Invited) Ultrafast Studies of Plasmonic and Photonic Structures for Energy Conversion Applications
Authors: Wiederrecht Gary P.
Published: December 2020

Hybrid materials with plasmonic and/or photonic components are of great interest for enhancing the efficiency of light harvesting and energy conversion processes. Those processes that occur on an ultrafast timescale can be very impactful on overall efficiencies of conversion, and therefore are important to understand. These processes can be, for example, the dynamics of hot plasmonic electron decay or the rate of excitonic migration within materials. In this talk, I describe studies of ultrafast spectroscopy and imaging in several types of plasmonic and photonic structures. These include the ultrafast plasmonic behavior of refractory metals and also gap plasmon metamaterials. Efforts to understand how to create greater numbers of energetic carriers, and how to monitor for their presence spectroscopically, are described. Also described are studies of exciton transport in biomimetic materials, particularly to understand how the concentration and orientation of chromophores impact the efficiency of exciton migration. Also described are metal-organic-frameworks and their relevance to supporting photoinduced exciton transport, with ultrafast photoluminescence used to characterize transport in optically scattering media. Finally I briefly describe the user science capabilities of the Center for Nanoscale Materials. This work was performed, in part, at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility, and supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
(Invited) Electric-Field Driven Selective Electrocatalytic CO2 Conversion
Authors: Kwon Youngkook
Published: December 2020

The efficient electrochemical conversion of CO2 to fuels or stock chemicals with high-energy density would be a major step forward in the introduction of a carbon neutral energy cycle. Especially, understanding the role of electrocatalysts, supports, and electrolytes that can efficiently reduce CO2 to fuels with high selectivity is a subject of significant interest.

One of the achievements in electrochemical CO2 reduction is the clarification of the catalysts toward two-electron involved products such as CO and formate. For instance, CO is selectively generated on Au, Ag, and single-atom catalysts and formate has been selective on Hg, Pb, Sn or alloy catalysts. Interestingly, from our recent work, CO/formate ratio can be selectively controlled on formate selective catalyst by tuning the interfacial electric field.[1] On copper catalyst, the selection of alkali cations has direct influence on activity and product selectivity; increasing the size of mono-valent cations can increase the activity and selectivity toward C-C coupled products by modulating the interaction energy between adsorbates and electric fields at the interface.[2] In addition, copper catalyst with a specific atomic-scale gap accelerates the reaction kinetics and selectivity to C2+ products.[3] Therefore, understanding the roles of catalyst, support and electrolyte offers the design of efficient, yet cheap electrochemical CO2 reduction systems.

[1] Y. Kwon et al., ACS Sustain. Chem. Eng.
2020, 8, 2117.

[2] Y. Kwon et al., J. Am. Chem. Soc.
2016, 138, 13006.

[3] Y. Kwon et al., Adv. Energy Mater.
2020, 1903423.
(Invited) Photo-Electrochemical Water and CO2 Reduction Devices Operating Under Concentrated Radiation
Authors: Haussener Sophia
Published: December 2020

Achieving high current densities while maintaining a high energy conversion efficiency is one of the main challenges for enhancing the economic competitiveness of solar fuel producing photo-electrochemical devices [1]. I will discuss two device implementations utilizing concentrated irradiation to achieve high current density operation: i) a water-splitting device, and ii) a CO2 reduction device. The water-splitting device is utilizing thermal integration to sustain high performance while dealing with high current density and the corresponding overpotentials [2]. The theoretical increase in the maximum efficiencies at given current densities of photoelectrochemical devices resulting from thermal synergies will be quantified, followed by discussion on the device implementation supported by more realistic device models (multi-dimensional, multi-scale, multi-physics) [3]. The presentation will end with a discussion and implementation of the same design principles to a CO2 reduction device. Experimental results of such a device will be discussed and the potential of high current density approaches for CO2 reduction devices will be quantified.

References

M. Dumortier, S. Tembhurne, S. Haussener, Energy Environmental Science, 8: 3614-3628, 2015.

S. Tembhurne, F. Nandjou, S. Haussener, Nature Energy, 4: 399-407, 2019.

S. Tembhurne, S. Haussener, Journal of The Electrochemical Society, 163: H1008-H1018, 2016.
Virtual Analysis of Gas-Diffusion-Electrode CO2 Electrolyzers
Authors: Weng Lien-Chun , Bui Justin C. , Romiluyi Oyinkansola , Bell Alexis T. , Weber Adam Z.
Published: December 2020

The electrochemical reduction of CO2 (CO2R) to value-added products is an attractive technology for tackling the rising atmospheric CO2 levels and storing intermittent renewable energy into chemical bonds. Fundamental understanding of CO2R has progressed significantly in recent years and is critical in the development of CO2R to liquid-fuel electrolyzers, where gas-diffusion electrodes (GDEs) have been shown to be key enabling architectures. Various designs have been proposed and studied in the literature to enhance overall selectivity, rates, and maximize the conversion of CO2, the latter of which is only now being recognized as a critical issue. In this respect, there is a need to explore the governing phenomena inherent in these architectures to enable optimization. Mathematical modeling is ideally suited to tackle and explore these multiphysics interactions and provide virtual design analysis.

In this talk, we discuss modeling methodologies and physics inherent in these devices and present our recent modeling of GDEs for CO2 reduction. We specifically examine the impacts of multiphase flow and related phenomena on overall cell performance. We then explore the performance and limitations of various cell designs guided by simulation results and examine potential methods for improving water management and tuning catalyst selectivity including the use of different anion-exchange and bipolar membranes. Finally, we discuss the disparities in local environments between aqueous and GDE devices and propose strategies to reduce the gap in knowledge between the two systems.

Acknowledgements

This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993.
Electrochemical Reduction of CO2 Using Carbon-Based Materials Modified with 3d-Metal Atoms As Electrocatalysts
Authors: Kamiya Kazuhide , Nakanishi Shuji
Published: December 2020

For the reductive CO2 fixation using solar energy, photo-generated electrons and/or holes must be captured and utilized for chemical reactions that generate products beneficial to humans. To construct the artificial photosynthesis systems, electron transfer catalysts designed to promote electrochemical CO2 reduction reactions (CO2RR) are a critical requirement. Previous studies have shown that precise tuning of adsorption energies of key intermediates is critical for obtaining high activity and reaction selectivity. There are two important factors that determine the adsorption energy of the intermediate on electrocatalysts. First, the metal species in the catalyst, i.e., the transition metals at the active sites with a higher number of d-electrons, tend to reduce the adsorption energy. Previous works have investigated the effects of metal species on the CO2RR using organometallic complexes as platforms to support various metals via coordination bonds. For example, cobalt-modified tetraphenylporphyrin (TPP) is known to exhibit efficient CO2RR activity due to its proper binding strength to COOH*, whereas nickel (Ni) and copper (Cu) modified TPP are known to have low catalytic activity due to the low binding energy of COOH*. The second critical factor is the coordination structure of the metal. First-principles calculations have revealed that a decrease in the coordination number of Pt and Cu in the bulk increases the bond strength of CO* and affects the activity of the CO2RR. Thus, it can be expected that the coordination number can be a control parameter to improve the performance of metal species that were previously thought to have no CO2RR activity. We have investigated the effects of metal species and the coordination structure on CO2RR using graphene and covalent triazine frameworks (CTF)[1,2]. CTF consisting of microporous conjugated polymers with 1,3,5-triazine linker units, are suitable for investigating the above issue due to the high design flexibility. Through the studies, we have revealed that Ni-modified graphene and CTF can work as efficient electrocatalysts for CO2RR due to the unsaturation nature of the Ni atoms on the substrate. In this talk, we report our systematic studies on CO2RR using carbon-based materials with 3d metal atoms, focusing on the effects of metal species and coordination structures.

[1] P. Su, K. Iwase, S. Nakanishi, K. Hashimoto, K. Kamiya, Small, 12, 6083-6089 (2016).

[2] P. Su, K. Iwase, T. Harada, K. Kamiya, S. Nakanishi, Chem. Sci., 9, 3941-3947 (2018).

Figure 1
2nd Generation Fourier Transform Electrochemical Impedance Spectroscopy with Commercial Potentiostat
Authors: Hwang Seongpil
Published: December 2020

The implementation of 2nd generation electrochemical impedance spectroscopy (2G-EIS) with commercial potentiostat will be presented. Compared with conventional EIS measurement based on frequency response analyzer (FRA), 2G-EIS based on potential step may offer the faster acquisition enabling time-resolved EIS. Unfortunately, complex home-built setup for 2G-EIS have been the obstacle for its application. We tried to measure the 2G-EIS with commercial potentiostat and software without frequency response analyzer (FRA) by virtue of commercial hardware and software. Most of current electrochemical instruments have sufficient power to digitize the electrochemical signal with high sampling rate thanks to recent state-of-the art electronics and software industry. The capability of this approach was estimated by the comparison with FRA. More to the point, in-situ time-resolved EISs during the formation of film will be presented.
In Situ X-Ray Absorption Spectroscopy Studies of Co9S8 Catalyst in Oxygen Evolution Reaction
Authors: Feng Zhenxing , Wang Maoyu
Published: December 2020

Transition metal sulphide are made from earth-abundant elements and show promising activity for oxygen evolution reaction for water splitting to generate clean fuels. However, these catalysts usually restructure to different composition and/or structure that are distinct from their initial states. Ex-situ characterizations on the such catalysts before and after reaction do not provide the meaning structure-property relationship. Therefore, it is necessary to use in-situ techniques to characterize catalysts in reactions. In this talk, I will show our recent work on Co9S8 which exhibits higher OER activity than RuO2. Using several in-situcharacterizations, particularly X-ray absorption spectroscopy (XAS), we not only directly observe how catalysts adjust their local structures and valence state to promote OER, but also identify the true reaction center. With help from density functional theory, we show that the di-m-oxo bridged Co-Co motif is the active site, which can be used for catalyst designs.
Probing Evolution of the Li/β-Li3PS4 Solid-State Electrolyte Interface
Authors: Seitzman Natalie , Al-Jassim Mowafak M. , Pylypenko Svitlana
Published: December 2020

With electric vehicle (EV) U.S. market share estimated at 2.1% in 2018, the transition to less carbon-emissive transportation is well underway.1 Solid state Li ion conductors are a next-generation battery technology that are particularly promising for EVs, offering the capacitive benefits of Li metal anodes while mechanically resisting evolution of the Li interface and thus prolonging lifetime. Additionally, solid electrolytes are not flammable, providing greater safety than liquid counterparts. Despite theoretical mechanical resistance, interface evolution and Li protrusions are empirically observed in solid state batteries and there is debate as to whether these protrusions nucleate at the Li anode or within the ceramic electrolyte.2,3 Variables that affect these protrusions include interfacial contact, imperfect electronic insulation within the electrolyte, electrolyte density, and pre-existing defects.3

Operando X-ray imaging is key to accessing the buried interface between the Li anode and solid electrolyte non-destructively and is a flexible technique that allows for control of factors that may influence the sites of Li microstructure growth as well as Li microstructure morphology.4,5 In this work, to understand the influence of these factors under realistic operating conditions, operando X-ray tomography is combined with in situ heating and pressure control. Cells of Li, β-Li3PS4 electrolyte, and a blocking contact are constructed and studied during cycling at elevated temperature and pressure. Electrolyte density and defects depend on the composition and synthesis of the ceramic conductor, therefore, two syntheses of electrolyte with different particle sizes are compared. Controlling pressure and temperature addresses the remaining factors of interest as pressure is a key parameter in the stability of interfacial contact while temperature affects the electronic, as well as the ionic, conductivity. Deconvoluting the influence of these variables on Li evolution and morphology is vital to understanding fundamental behaviors of all-solid batteries under realistic conditions.

R. Irle, EV-volumes.com (2019) http://www.ev-volumes.com/country/usa/.

E. J. Cheng, A. Sharafi, and J. Sakamoto, Electrochim. Acta, 223, 85–91 (2017).

F. Han, A. S. Westover, J. Yue, X. Fan, F. Wang, M. Chi, D. N. Leonard, N. J. Dudney, H. Wang, and C. Wang, Nat. Energy (2019).

N. Seitzman, H. Guthrey, D. B. Sulas, H. A. S. Platt, M. Al-Jassim, and S. Pylypenko, J. Electrochem. Soc., 165, 3732–3737 (2018).

E. Kazyak, S. William, C. Haslam, J. Sakamoto, N. P. Dasgupta, E. Kazyak, R. Garcia-mendez, W. S. Lepage, A. Sharafi, A. L. Davis, A. J. Sanchez, K. Chen, C. Haslam, J. Sakamoto, and N. P. Dasgupta, Matter, 2, 1025–1048 (2020).
Elucidating the Role of Strain in Promoting C-C Coupling on Cu Surfaces
Authors: Kim Taewoo , Fenning David P
Published: December 2020

The design of CO2 reduction catalysts with high selectivity toward energy-dense, multi-carbon products remains a challenge. In this study we demonstrate a substantial correlation between surface strain and selectivity in aqueous CO2 reduction on model Cu (001) surfaces. By tuning the thickness of epitaxially-grown Cu layers on Si (001) substrates, we vary the lattice mismatch-derived tensile strain that remains. In-plane X-ray diffractometry indicates an increasing in-plane strain, up to 0.48%, is achieved in Cu epitaxial layers as layer thickness decreases from 100 nm to 20 nm. A roughly order-of-magnitude enhancement in selectivity to multi-carbon products (C2H4, acetate, EtOH, and n-PrOH) as compared to single-carbon products (formate, CO, and CH4) in 0.1M KHCO3 electrolyte is seen with this increase in built-in strain, evidencing the tuning of the adsorption energy of key reaction intermediates. Moreover, the strained 20 nm epitaxially-grown Cu thin films exhibit 4.8x and 68.3x higher selectivity to multi-carbon products as compared with bulk single-crystal Cu(100) and polycrystalline Cu surfaces. The enhanced selectivity toward energy-dense products can be attributed to an increased adsorption energy of selectivity-determining intermediates such as *CO and *CHO on the strained surface and promotion of C-C coupling reaction. These findings indicate the opportunity for rigorous strain engineering to modify adsorption energy of key intermediates for enhanced selectivity in CO2 reduction.

Figure. Characteristics and CO2 reduction performance of epitaxially grown Cu (001) thin film on Si (001) substrate. (a) Bulk in-plane tensile strain as a function film thickness. Selectivity ratio of (b) C2H4 to CH4 and (c) multi-carbon products to single-carbon products as a function of bulk in-plane tensile strain at -0.9V vs RHE in CO2-saturated 0.1 M KHCO3 electrolyte.

Figure 1
(Invited) The Electrochemical CO2 Reduction Reaction: Understanding the Selectivity of the Cu Catalyst
Authors: Bagger Alexander
Published: December 2020

Electrochemical CO2 and CO reduction holds the promise to be a cornerstone for sustainable production of fuels and chemicals. However, it is a complex reaction which give multiple different products depending on metal catalyst [1]. The product distributions on the metals catalyst can be understood by ignoring the reaction pathways and grouping the multiple metal catalyst by their product selectivity [2]. It shows that, the unique copper catalyst, as the only metal catalyst has the ability to bind CO* while not having hydrogen under potential deposited (UPD), which results in a high value multiple-carbon product distribution. Furthermore, the exotic product distribution has been shown to be dependent on the exact crystal orientation of the Cu facets for the Cu catalyst [3,4]. Consequently, understanding and improving the product selectivity of the Cu catalyst is a complex property to understand.

In this talk I will discuss the properties of the Cu catalyst: (1) How is the products from the Cu catalyst facets related to each other and how they can be grouped. (2) How can descriptors and models be built to understand and guide the product distribution of the Cu catalyst toward selective high value products [5].

[1] Y. Hori et. al., Journal of the Chemical Society, Faraday Transactions, 1989, 85, 2309-2326.

[2] A. Bagger et. al., ChemPhysChem, 2017, 18, 3266–3273.

[3] Y. Hori et. al., Journal of Molecular Catalysis A: Chemical, 2003, 199, 39-47.

[4] K. J. P. Schouten et. al., Journal of the
American Chemical Society, 2012, 134, 9864-9867.

[5] A. Bagger et. al., ACS Catal.
2019, 9, 9, 7894–7899.
Hybrid Copper Macrocycle/Nickel-Nitrogen Doped Graphite for Aqueous Electrochemical Carbon Dioxide Reduction
Authors: Lee Jack , Asset Tristan , Atanassov Plamen , Minteer Shelley D.
Published: December 2020

Increasing levels of carbon dioxide in the atmosphere has led to adverse effects on the environment due to climate change. These negative effects have stimulated efforts to develop ways to capture carbon dioxide. The issue is what to do with it when it is captured since its current uses are limited. Therefore, identifying catalysts that can reduce carbon dioxide into useful chemicals is a potential solution to this impending problem. Using electrocatalysis could be even more advantageous as it could allow for the use of renewable energy to directly fix carbon. Depending on the final use of the reduced products, whether as fuels or materials, the net effect on carbon dioxide in the atmosphere would be neutral or negative respectively.

Combining catalysts that can work together to help make carbon dioxide electrolysis products is the strategy employed in this work. A variety of metal/nitrogen-doped graphite electrocatalysts were screened for their activity for carbon dioxide reduction. These carbon-based metal/nitrogen catalysts primarily produce carbon monoxide from carbon dioxide. For this reason, several different metallized porphyrins and phthalocyanines were tested for their ability to reduce carbon monoxide, as they can be easily attached to the graphitic catalysts. Copper phthalocyanine has been shown to be an effective catalyst for both carbon monoxide and carbon dioxide reduction. Nickel/nitrogen doped graphite when used with copper phthalocyanines has shown promise as a way of increasing the relative amount of two carbon products. So far combining the two catalysts has been shown to increase the amount of ethylene relative to the amount of methane by a factor of six, compared to using the copper phthalocyanine by itself.
(Keynote) Decoupled Electrolysis for Water Splitting and Beyond
Authors: Symes Mark
Published: December 2020

The storage of renewably-generated energy as hydrogen via the electrolysis of water is a fundamental cornerstone of a sustainable hydrogen economy. Conventional electrolysers usually require stable power inputs in order to operate effectively and safely and so may be unsuited to harnessing renewable power, which is often intermittent and diffuse. Electrolysis mediated by Electron-Coupled-Proton Buffers (see, for example: Nature Chem.
2013, 5, 403-409; Science,
2014, 345, 1326-1330; J. Am. Chem. Soc.
2016, 138, 6707–6710; Joule, 2018, 2, 1390-1395) has the potential to overcome some of the challenges surrounding electrolysis using low and/or sporadic power inputs (especially those related to gas crossover) as the use of Electron-Coupled-Proton Buffers allows the oxygen and hydrogen evolution reactions to be completely decoupled from one another. In this talk, we shall investigate these claims for decoupled electrolysis (Electrochim. Acta,
2020, 331, 135255) and also explore the use of Electron-Coupled-Proton Buffers in new contexts such as redox flow batteries (Nature Chem.
2018, 10, 1042-1047) and electrochemical CO2 reduction.
(Invited) New Ionic Liquids (ILs) for Secondary Batteries: Interplay between Structure, Electrical Response and Conductivity Mechanism
Authors: Vezzu Keti , Pagot Gioele , Negro Enrico , Di Noto Vito
Published: December 2020

The main bottleneck towards the development of high-performing “beyond Lithium ion” batteries in the portable electronic, electric automotive, and stationary applications [1] is the lack of electrolytes that are safe, electrochemically stable, and compatible with the electrode materials [2-3].

Recently published papers demonstrated that halo-aluminate ionic liquids (ILs) can provide an appealing alternative to conventional ethereal solvent-based electrolytes due to their low volatility, negligible flammability, and excellent electrochemical performance [4-7].

Following this, an overview on recent advancements on electrolytes for secondary batteries is presented, with a particular reference to imidazolium- and pyrrolidinium-based ILs. Insights on the interplay between thermal properties, structure and conductivity of BF4
-, Cl-/AlCl3, Cl-/TiCl4, and I-/AlI3-based systems are given, thus providing an in-depth understanding of the relation existing between ion speciation, long-range charge transfer mechanism, conductivity mechanisms and electrochemical performance of this very promising class of materials.

References

[1] B. Dunn, H. Kamath, J. M. Tarascon, Science 334 (2011) 928-935.

[2] V. Di Noto, T. A. Zawodzinski, A. M. Herring, G. A. Giffin, E. Negro, S. Lavina, Int. J. Hydrogen Energy 37 (2012) 6120-6131.

[3] B. Scrosati, J. Garche, J. Power Sources 195 (2010) 2419-2430.

[4] F. Bertasi, C. Hettige, F. Sepehr, X. Bogle, G. Pagot, K. Vezzù, E. Negro, S.J. Paddison, S.G. Greenbaum, M. Vittadello, V. Di Noto. ChemSusChem. 8 (2015) 3069-3076.

[5] F. Bertasi, F. Sepehr, G. Pagot, S.J. Paddison, V. Di Noto. Adv. Funct. Mater. 2016, 26, 4860-4865.

[6] F. Bertasi, K. Vezzù, G. Nawn, G. Pagot, V. Di Noto. Electrochim. Acta. 2016, 219, 152-162.

[7] G. Pagot, F. Bertasi, K. Vezzù, F. Sepehr, X. Luo, G. Nawn, E. Negro, S.J. Paddison, V. Di Noto. Electrochim. Acta. 2017, 246, 916-923.
Engineered Electrolyte-Electrocatalyst Nanocomposites for Enhanced CO2 Electroreduction
Authors: Elgammal Ramez A. , Zawodzinski Thomas Anthony
Published: December 2020

The development of a viable approach to capture, store, and convert carbon dioxide into fuels and chemicals may offer a means to mitigate climate change while also creating value added commodity chemicals. Critical bottlenecks in existing technologies that have impeded commercialization of CO2 electrosynthesis include catalysts with high overpotentials and limited selectivities. Furthermore, current approaches often employ PEM-based electrolyzers that suffer from low CO2 solubility in acidic aqueous solutions, limiting mass transport and reaction rates, or AEM-based systems which have much higher CO2 solubilites in alkaline electrolytes, but have the added problem of membrane poisoning by bicarbonate and carbonate.

We have recently developed an electrochemical reactor that overcomes many of the shortcomings that have limited the above technologies. Our preliminary results suggest that onset potentials for CO2 reduction are more than 200 mV lower than with current densities in excess of 150 mA/cm2 at -1 V vs RHE. The selectivities for CO are in excess of 90% and the electrocatalysts. We have examined several cathode electrocatalysts and some of the most promising include a series of nanostructured mixed and/or doped transition metal and main group metal oxides that also suppress the hydrogen evolution reaction. We will present detailed electrochemical and structural studies and will comment on possible reaction mechanisms as well as the key features of the reactor that enable the enhanced kinetics.
Zinc-Catalyzed Electrocatalytic Hydrogenation of Furfural at Neutral pH
Authors: Dhawan Manali , Yadav Ganapati Dadasaheb , Calabrese Barton Scott
Published: December 2020

Electrocatalytic hydrogenation (ECH) of biomass-derived platform chemicals is a sustainable way to produce value added fuels and chemicals as compared to chemo-catalytic hydrogenation pathway [1,2]. In this work, ECH of furfural was carried out to produce furfuryl alcohol (FAL) and 2-methylfuran (MF) which have applications in pharmaceutical, polymer and fuel industries [1-3]. In this work, Zn metal was used as a novel catalyst for the ECH of furfural to study its yield and Faradaic efficiency (FE) for the desired products. The activity of Zn metal was compared to the well-known catalysts such as Cu and Ni. The effect of electrolyte pH was also studied, and it was found to significantly affect FE and product profile. Potentiostatic electrolysis in acidic and basic pH electrolytes suffered from poor product yield and FE, either due to dominant hydrogen evolution reaction (HER) or degradative electrodimerization and polymerization reactions. Electrolysis at neutral pH (pH 6 to 8) exhibited increased yields and FE as compared to acidic and basic pH. We correlate this to optimum proton concentration in neutral electrolytes that would restrict HER in addition to providing a pH atmosphere that would minimize side reactions. At neutral pH, the reaction was more selective towards FAL formation than MF. The best activity of Zn catalyst was obtained with 0.5 M sodium bicarbonate (NaHCO3) electrolyte (pH = 8.4) at -0.7 V/RHE with 77.5 % FE for FAL. The zinc catalyst displayed a total FE of 94 % for the ECH of furfural. At the same reaction conditions, the conversion, yield and FE for ECH with Zn was remarkably higher as compared to Cu and Ni metal electrodes. Zinc oxide precipitates were observed on the wire during electrolysis and were confirmed by EDS. The increased activity of Zn suggests a mechanistic role of adhered ZnO precipitates, possibly enhancing H adsorption and transfer to furfural.

References:

[1] Z. Li, S. Kelkar, C.H. Lam, K. Luczek, J.E. Jackson, D.J. Miller, C.M. Saffron, Aqueous electrocatalytic hydrogenation of furfural using a sacrificial anode, Electrochim. Acta. 64 (2012) 87–93. doi:10.1016/j.electacta.2011.12.105.

[2] X.H. Chadderdon, D.J. Chadderdon, J.E. Matthiesen, Y. Qiu, J.M. Carraher, J.P. Tessonnier, W. Li, Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates, J. Am. Chem. Soc. 139 (2017) 14120–14128. doi:10.1021/jacs.7b06331.

[3] S. Jung, E.J. Biddinger, Electrocatalytic Hydrogenation and Hydrogenolysis of Furfural and the Impact of Homogeneous Side Reactions of Furanic Compounds in Acidic Electrolytes, ACS Sustain. Chem. Eng. 4 (2016) 6500–6508. doi:10.1021/acssuschemeng.6b01314.

Figure 1
(Invited) Anodic TiO2 Nanostructures for Photoelectrochemical and Photocatalytic Applications
Authors: Lee Kiyoung
Published: December 2020

Since Zwelling et al. reported on anodized TiO2 nanotubes, many research groups have studied one-dimensional TiO2 nanotubes. This structure property can be controlled by pH, conductivity, fluoride concentration, base solution and applied potential and so on. TiO2 nanotubes are attracted attention owing to their variable function for use wide range applications such as photocatalyst, bio application, template and solar cell, etc. TiO2 nanotubes provide smooth electron pathway, less crystal defect to avoid electron recombination, high surface area for dye adsorption and the ability influence the adsorption and propagation of light.

In this presentation we give an overview of the latest results on TiO2 nanotube and porous structures. We will discuss critical factors to grow highly aligned and high aspect ratio anodic TiO2 nanostructures and the morphological variation by anodization parameters and their advantage for photocatalytic and photoelectrochemical applications.