bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Development of Energy-Efficient and Scalable Electrochemical Devices for CO2 to Formate Conversion
Authors: Hu Leiming , Intia Fry , Wrubel Jacob A , Baez-Cotto Carlos , Saha Prantik , Lou Kun , Neyerlin Kenneth C. 
Published: September 2023

CO2 electrochemical reduction to useful chemicals has drawn significant interest over the past decade, as the technology shows promising potential for coupling with renewable energies and helping reduce the overall CO2 emission.1 Among different CO2 reduction (CO2R) end products, formate has some economic advantages because it is easier for downstream separation as a liquid product, and has many applications, such as hydrogen storage 2 and biomass conversion3. Several studies have shown that using SnO2 or Bi-based catalyst, the Faradaic efficiency (FE) for CO2 to formic acid/formate can be high (>80%).4,5 However, many literature-reported CO2 to formic acid/formate systems either has very high cell voltage during operation or contain complex chamber structures that induces large Ohmic drops or make it very hard for scaling up.
In this study, we explored different pathways for CO2 to formate electrochemical conversion that are both energy-efficient and scalable. Several cell configurations were investigated regarding cell voltage, energy consumption, and FE. As shown in Figure 1a, by optimizing the cell configuration, we can get the cell voltage 50% lower compared to the previous reported bipolar membrane with catholyte chamber configuration. The FE is 80.1% at 400 mA/cm2 and 79.5% at 500 mA/cm2. The overall energy consumption of the formate production is < 0.2 kWh/mol. We will talk about the advantage of different cell configurations we explored and the stability of each of those systems.

Figure 1
Optimizing the Design and Fabrication of Membrane Electrode Assemblies for High Performance CO2 Electrolyzers
Authors: Kabir Sadia , Ye Nancy , Waldrup Mark , Kuhl Kendra 
Published: September 2023

The electrode layer is a critical component of low-temperature polymer electrolyte membrane electrochemical devices such as fuel cells and CO2 electrolyzers. The electrode has a major impact on the device’s efficiency, high current density performance and long-term durability. As such, the rational design and fabrication of electrode structures and interfaces with optimal component interactions, ionic and gas phase accessibility, as well as water management properties is crucial for advancing the performance, durability and economic viability of these electrochemical devices.
Typically, membrane electrode assemblies are manufactured using fabrication techniques such as roll to roll, electrospinning or ultrasonic spray coating. These methods rely on homogenizing the catalysts, ionomers, solvents, and any other polymeric additives into a colloidal ink and depositing them onto a substrate. At the microscopic level, the combination of electrostatic repulsion and Van der Waals attraction between the individual constituents (solvent, catalyst, polymer) can alter the macroscopic properties (i.e. viscosity, surface tension, rheology) of the colloidal inks. These properties are relevant for coating and MEA manufacturing processes, as the net interparticle interaction potentials determine the tendency of particles to aggregate or disperse which impacts tortuosity, density and porosity of the deposited layer. .
As such, optimizing component interactions is crucial for improving particle dispersion, drying behavior and stability of inks to fabricate high performance defect-free electrodes. Its imperative to expand our understanding of structure-property relationship between MEA composition and electrochemical characteristics (i.e. CO selectivity, HFR, mass/charge transport) to fabricate electrodes with high CO2 conversion efficiencies. Elucidating how composition (loading/thickness) morphology (porosity, surface roughness) and architecture (ionomer coverage, additives) of the catalyst layer and in turn its resulting impact on short term and long term performance will determine the commercial viability of CO2 electrolysis systems. This talk will highlight current R&D advancements in understanding of component interactions (i) for integrating high performance materials in electrodes for industrially relevant CO2 reduction applications, ii) improving electrode structure to maximize active site utilization and iii) mitigating mass transport limitations at catalyst-ionomer interface with a focus on understanding decay mechanisms.
Enhancing Electrocatalytic Conversion of Bicarbonate to Formate by Via Bismuth Alloys
Authors: Wong Andrew Barnabas 
Published: September 2023

The bicarbonate reduction reaction has been emerging as a promising approach for converting CO2-riched medium to profitable products. However, the reduction of bicarbonate to formate still requires further development to achieve a moderate faradic efficiency. Herein, we introduced a low hydrogen-affinity metal (indium) into bismuth-based materials for BRR. It shows a favorable FEformate of 84.81%, a considerable formate partial current density of 241 mA∙cm-2, and a superior formate generation rate of 56 mmol∙L-1∙cm-2∙h-1.
Comprehensive ex-situ XRD characterization suggests that the incorporation of indium will inhibit the phase transformation from metallic bismuth to a bismuth subcarbonate species, which leads to the enhanced performance for bicarbonate reduction to facilitate improved cathodic formate production from the In-Bi alloy as compared to pure Bi.
Intercalation of Potassium Ions in Molybdenum Sulfide as Catalyst for CO2 Reduction
Authors: Mádai Eszter , Mol Arjan , Hartkamp Remco , Taheri Peyman 
Published: September 2023

The increasing CO2 emission during the last decades highly contributed to global warming and as a consequence, we are facing the disruption of nature and more and more extreme weather conditions nowadays [1]. One way of dealing with the emitted excess CO2 is to create a synthetic carbon cycle, where the emitted CO2 is captured and turned into fuel using electrocatalysis and green energy. However, in order to achieve this, the exploration of new electrocatalysts is needed for the sake of cost and process efficiency and environmental friendliness.
Two dimensional materials have a promising future as catalysts due to their high surface-to-volume ratio. A potential catalyst material for CO2 reduction is molybdenite (MoS2), a cheap, layered semiconductor which already showed selectivity towards CO2 reduction in non-aqueous media [2,3]. Its layered structure allows not only to have a high specific surface area but also makes the intercalation of different ions possible. These features enable us to enhance the conductivity of the material via electron donation by the intercalated species [4]. The improved conductivity and the changed band gap can contribute to a higher efficiency of electrochemical processes.
Our research investigates the intercalation mechanism of potassium ions into MoS2 layers and the effects of the intercalated potassium on the CO2 reduction efficiency. The intercalation process is studied experimentally through electrochemical impedance spectroscopy (EIS) and confirmed by X-ray diffraction (XRD). Furthermore, the Gibbs free energy profile of the intercalation is obtained by Molecular Dynamics (MD) simulations using umbrella sampling. The electronic properties are measured with X-ray photoelectron spectroscopy (XPS) and the products of the CO2 reduction reaction is measured with gas chromatography (GC). The results suggest that the potassium intercalation improves the conductivity of the MoS2 and consequently the CO2 reduction efficiency.
[1] McCrystall et al. New climate models reveal faster and larger increases in Arctic precipitation than previously projected. Nat. Commun. 12:6765, 2021.
[2] Asadi et al. Robust carbon dioxide reduction on molybdenum disulphide edges. Nature Communications, 5(1), 2014.
[3] Asadi et al. Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid. Science, 353(6298):467–470, 2016.
[4] Wang et al. Atomic-scale clarification of structural transition of MoS2 upon sodium intercalation. ACS Nano, 8(11):11394– 11400, 2014.
Large-Scale and Highly Selective Electrochemical CO2 to C2H4 Conversion Based on the Giner Water Management GDL
Authors: Zhang Tianyu , Pupucevski Max , Ding Shuo , Lattimer Judith 
Published: September 2023

C2H4 is a key building block in the chemical industry to produce a wide range of plastics, solvents, cosmetics, etc. On average, the production of 1 MMT of C2H4 generates 1.5 MMT of CO2, coming from fuel combustion, decoking, and utilities. Globally, C2H4 production by steam cracking is ranked as the second-largest contributor of energy consumption (2.8 EJ/year) and greenhouse gas emissions (300 MMT of CO2-e/year) in the chemical industry. Electrochemical CO2 reduction reaction (CO2RR) to produce C2H4 at ambient conditions, when coupled with renewable electricity, could reduce dependence on fossil fuels and decarbonize the chemical sector associated with C2H4 production. However, more efforts are needed to improve selectivity, productivity, and durability before the CO2 electrolyzer can be deployed commercially.
State-of-the-art continuous CO2 electrolyzers utilize gas diffusion electrodes (GDEs) to achieve CO2-to-C2H4 conversion at industrially relevant current density. However, managing the flooding of liquid electrolytes into the porous structure of GDE remains a critical practical challenge for stable and efficient CO2 transport. To date, most CO2 electrolyzers used commercial gas diffusion layer (GDLs) designed for polymer electrolyte membrane fuel cells (PEMFC), which operate under different conditions than CO2RR. The conventional GDL is generally made of carbon paper coated with 5-30 wt.% of polytetrafluoroethylene (PTFE) to protect against flooding. These GDLs still lose hydrophobicity fast during CO2 electrolysis at highly negative potentials due to the electrowetting of carbon materials, salt precipitation, and chemical degradation. As a result, the electrolyte even penetrates the micropores of the GDL, blocking CO2 transport to catalyst sites.
Giner has designed an innovative structure, the water management GDL (WM-GDL), providing a breakthrough solution for water management under the operational conditions of a CO2 electrolyzer. The WM-GDL has dedicated mass transport pathways for gas and electrolyte, which allows durable and efficient mass transport of both over long-term operation. The utilization of WM-GDL will assist in the scale-up of electrochemical CO2-to-C2H4 conversion. Currently, the state-of-the-art WM-GDL achieved 60% C2H4 selectivity at 500 mA cm-2 and 3 V in a 50 cm2 MEA electrolyzer. Larger-scale demonstration of the CO2-to-C2H4 conversion with high selectivity and durability will be carried out in stacks.

Acknowledgment: The project is financially supported by the Department of Energy’s Office of EERE under the Grant DE-EE000942l
Suppressing Gas Evolution in Li4Ti5O12||LiNi1/3Co1/3Mn1/3O2 Pouch Cells By High Temperature Formation
Authors: Alsheimer Lennart , Peschel Christoph , Dienwiebel Iris , Winter Martin , Börner Markus 
Published: September 2023

The increasing demands for a wide range of lithium-ion battery (LIB) applications requires the development of both improved high-energy as well as high-power systems. However, for high-power applications, the performance and thermal stability window of most commercial LIB systems is very limited. To meet these requirements, the spinel-type active material Li4Ti5O12 (LTO) is a very prominent candidate as an alternative to conventionally used graphite as a negative active material for LIBs. However, despite the excellent lifetime and safety properties of LTO [1], its commercialization is still hindered by severe gas evolution during cyclic and calendar aging [2,3].
This study demonstrates that elevated temperatures during the formation procedure do not only suppress gas evolution upon subsequent charge/discharge cycling but also have a positive impact on the specific discharge capacity and rate capability. It was shown by same-spot SEM investigations that higher formation temperatures lead to the formation of a homogeneous decomposition layer over the entire electrode surface area. Volume measurements of the cells showed, that an increase in formation temperature is furthermore associated with more gas evolution, suggesting that gas evolution and decomposition layer formation are directly correlating.
It is assumed that the formation of this decomposition layer on the LTO electrode surface during the formation procedure essentially serves to reduce or (in case of applying sufficiently high formation temperatures) even suppress surface catalytic gassing reactions during subsequent cell application.
In this context, the impact of the electrode surface area on the qualitative and quantitative gassing behavior during cell aging is highlighted. In contrary to the assumption that LTO is solely responsible for gas evolution in LTO-based LIBs, it could be shown that gas evolution is primarily determined by the specific electrode surface area. Accordingly, when LTO is used as negative active material, a protective layer for suppression of gas evolution should be formed not only on the active material particles but also on the inactive surface are, hence, the entire electrode surface area.
Therefore, the high-temperature formation approach presented in this study is ideally suited for formation of an effective decomposition layer over the entire electrode. Since neither particle pretreatment nor the addition of film-forming electrolyte additives were necessary to suppress severe gas evolution, the high temperature formation approach could be the cornerstone for a cost-effective and easy commercialization of Li4Ti5O12-based cells.
[1] C. Han, Y.B. He, M. Liu, B. Li, Q.H. Yang, C.P. Wong, F. Kang, J. Mater. Chem. A, 2017, 5, 6368–6381
[2] K. Wu, J. Yang, Y. Liu, Y. Zhang, C. Wang, J.Xu, F. Ning, D. Wang, J. Power Sources, 2013, 237, 285.
[3] S. Wang, J. Liu, K.Rafiz, Y. Jin, Y. Li, Y. S. Lin, J. Electrochem. Soc., 2019, 166, A4150.
(Invited) Understanding the Role of Dopants (Al, Zn, Zr) in Altering Charge-Storage Capacity and Cycling Profiles of VFe2Ox
Authors: Johannes Michelle D. , Swift Michael W , Bernstein Noam , DeBlock Ryan H. , Ford Hunter O. , Chervin Christopher N. , Rolison Debra R. , Long Jeffrey W. 
Published: September 2023

Vanadium ferrite (VFe2Ox) is a defective spinel system that can incorporate substantial Li+ and exhibits a high charge–discharge rate, particularly when structured as a nanoscale aerogel.1 Cations such as Zr, Zn and Al,2 can readily enter the structure substitutionally and have strong, but differing effects on the charge-storage capacity of the material. These earth abundant, cost- effective constituent elements give this class of materials strong potential as future Li-ion battery cathodes but optimizing the stoichiometry for maximum capacity and stability will require understanding the redox sequence of the host cations (Fe, V) and role of intentional dopants.
We use density functional theory calculations in concert with in situ and operando X-ray absorption near-edge spectroscopy (XANES) spectra obtained using an in-lab X-ray absorption spectrometer to uncover the quantum mechanical-level effects that underpin relevant energy- storage behaviors of doped and undoped VFe2Ox. Our experimental V K-edge and Fe K-edge spectra indicate reduction of both species during discharge but cannot distinguish between tetrahedral and octahedral Fe redox sites or fully resolve the valency of each element as a function of state of charge. Using a hybrid form of density functional theory that accounts for the strong correlation present in 3d elements, we show that both V and Fe are indeed reduced, but that only tetrahedral Fe is redox active until fully converted to Fe2+. Furthermore, both octahedral and tetrahedral Fe3+ are high spin configuration, but the 5μB moments in the fully filled majority spin channel at each symmetry site are anti-aligned. This arrangement allows for easy exchange of electrons and facilitates conduction. We also calculate XANES spectra based on first principles calculations to be compared directly to those measured in the lab. This cross- check allows us to understand the effect of Al, Zr, and Zn dopants on the redox sequence and relate these results to site preference and capacity. Our combined experimental and calculational investigation sheds light on how these complex materials store Li ions and points toward future alterations that may further improve their properties.
Localized Tortuosity Determination of Li-Ion Battery Electrode Using SECM and SICM
Authors: Raju Anjana Raj , Danis Andrew , Schougaard Steen Brian 
Published: September 2023

Li-ion batteries’ limited power represents a barrier to their application in the domain of renewable energy. To examine the origin of this limitation, the effect of microstructural parameters such as porosity and tortuosity on ionic transport, especially through the electrolyte within the electrode pores needs to be studied. In this work, we tried to determine the local tortuosity in Li4Ti5O12 (LTO) electrodes with various porosities using two scanning probe microscopic techniques: Scanning Ion Conductance Microscopy (SICM) and Scanning Electrochemical Microscopy (SECM). SICM measures the effective ionic conductivity of Li+ ions whereas SECM probes the diffusion of electroactive species like anthracene.1,2 We observed that in both cases, the normalized current increases with porosity as more ions reach the tip through the pores of the electrode. The MacMullin number calculated from SICM and SECM measurements for the LTO electrodes having porosities from 50% to 63% shows that these techniques are complementary. Improved transport through these porous electrodes is indicated by the lower tortuosity values obtained compared to those anticipated by the mass transport models like the Bruggeman relationship. Hence, the tortuosity values determined from these microscopic techniques can be used as a strong tool to improve the modeling of electrolyte transport within electrodes. In turn, this should be highly valuable in the design of batteries with high power density.
References:

N. A. Payne, J. I. G. Dawkins, S. B. Schougaard and J. Mauzeroll, Anal. Chem., 2019, 91, 15718–15725.

Md. S. Hossain, L. I. Stephens, M. Hatami, M. Ghavidel, D. Chhin, J. I. G. Dawkins, L. Savignac, J. Mauzeroll and S. B. Schougaard, ACS Appl. Energy Mater., 2020, 3, 440–446.
(Invited) Development and Application of Titration Gas Chromatography in Elucidating the Behavior of Anode in Lithium Batteries
Authors: Bao Wurigumula , Meng Ying Shirley 
Published: September 2023

The accelerated transition to renewable energy systems worldwide has triggered increasing interest in energy storage technologies, especially in lithium batteries. Accurate diagnosis and understanding of the batteries degradation mechanism are essential. Titration Gas Chromatography (TGC) has been developed to quantitively understand the anode. The inactive Li in the cycled anode can be categorized into two kinds: 1) trapped Li0 (such as trapped lithiated graphite (LixC6), Li0, and lithium silicon alloy (LixSi)) and 2) solid electrolyte interphase (SEI) Li+. Noted that only trapped Li0 can react with the protic solvent to generate the hydrogen (H2), while SEI (Li+) does not1. Therefore, the H2 gas quantification can be correlated to the trapped Li0 as the foundation mechanism of TGC. With the optimal solvent selection, we successfully applied TGC to investigated: 1) the degradation behavior of Si-based anode materials2, 3; 2) corrosion effects on electrochemically deposited Li metal anode4; 3) the cycling behavior of Gr anode; 4) Li inventory quantification in practical Li metal battery5. We demonstrate the various application of TGC techniques in quantitatively examining the Li inventory changes of the anode. Beyond that, the results can provide unique insights into identifying the critical bottlenecks that facilitate battery performance development.
References:

Fang, C.; Li, J.; Zhang, M.; Zhang, Y.; Yang, F.; Lee, J. Z.; Lee, M. H.; Alvarado, J.; Schroeder, M. A.; Yang, Y.; Lu, B.; Williams, N.; Ceja, M.; Yang, L.; Cai, M.; Gu, J.; Xu, K.; Wang, X.; Meng, Y. S., Quantifying inactive lithium in lithium metal batteries. Nature
2019,
572 (7770), 511-515.

Bao, W.; Fang, C.; Cheng, D.; Zhang, Y.; Lu, B.; Tan, D. H.; Shimizu, R.; Sreenarayanan, B.; Bai, S.; Li, W., Quantifying lithium loss in amorphous silicon thin-film anodes via titration-gas chromatography. Cell Reports Physical Science
2021,
2 (10), 100597.

Sreenarayanan, B.; Tan, D. H.; Bai, S.; Li, W.; Bao, W.; Meng, Y. S., Quantification of lithium inventory loss in micro silicon anode via titration-gas chromatography. Journal of Power Sources
2022,
531, 231327.

Lu, B.; Li, W.; Cheng, D.; Bhamwala, B.; Ceja, M.; Bao, W.; Fang, C.; Meng, Y. S., Suppressing chemical corrosions of lithium metal anodes. Advanced Energy Materials
2022, 2202012.

Deng, W.; Yin, X.; Bao, W.; Zhou, X.; Hu, Z.; He, B.; Qiu, B.; Meng, Y. S.; Liu, Z., Quantification of reversible and irreversible lithium in practical lithium-metal batteries. Nature Energy
2022,
7 (11), 1031-1041.
(Invited) Improving Calendar Life of Si-Based Lithium-Ion Batteries By FEC/VC-Free Electrolytes
Authors: Kim Ju-Myung , Cao Xia , Yi Ran , Zhang Ji-Guang 
Published: September 2023

Silicon (Si) has been regarded as one of the most promising anode materials for the next generation lithium-ion batteries (LIBs) with high energy density because it has 10 times higher theoretical specific capacity (4200 mAh/g) than that of graphite. However, severe volume change (~300%) of Si during lithiation and delithiation hinders the practical application of Si anode. In the last decade, significant progresses have been made on the specific energy and cycle life of Si based LIBs. However, calendar-life of these batteries is still far less than 10-year target required by DOE’s electrical vehicle (EV) project.
In the current work, the role of FEC/VC in conventional carbonate electrolytes has been investigated. It has been found that FEC/VC causes large impedance growth on both Si and graphite anodes at 55 oC. The cut-off voltage of NMC622 has been found to significantly affect its impedance. NMC622 at 4.2V shows no impedance growth at 55 °C for 8 days, while severe impedance growth is observed at 4.4V. To address the instability of both SEI and CEI at elevated temperature, a new Localized High Concentration Electrolyte (LHCE) has been developed to improve the calendar life of Si based LIBs by effectively limiting impedance growth of Si/NMC622 full cells. In addition, the cycle life of the full cell is improved. The mechanism of Si full cells with improved calendar life will also be discussed.