bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Exploring Solar-Driven CO2 Reduction to C2+ Products
Authors: King Alex J , Bui Justin C. , Kim Chanyeon , Wei William , Kim Keon-Han , Safipour John , Kusoglu Ahmet , Toma Francesca Maria , Bell Alexis T. , Weber Adam Z. 
Published: February 2024

Use of solar irradiance to drive CO2 reduction (CO2R) holds great promise for the sustainable generation of energy-dense fuels and chemicals, especially as it relates well to carbon capture technology. Multicarbon (C2+) products (e.g., ethylene, ethanol, propanol) are particularly attractive because they have a large market size and can be further converted to higher molecular weight hydrocarbons fuels that have high volumetric and mass energy densities. Metallic copper (Cu) has the unique ability to catalyze CO2 to C2+ products with high faradaic efficiency; however, the product distribution of CO2R on Cu is potential and microenvironment dependent. In this talk, we will explore CO2R via different routes using both experiments and simulation. We will focus on obtaining C2+ products via tailoring the microenvironments including the use of ionomer films that are quite effective at the lower current densities that match against the solar irradiance. We will demonstrate how control of the local environment and dynamic operation provide metastable states of high pH and high CO2 concentration, thereby enabling high CO2R to C2+ production.
In addition, for direct photoelectrochemical CO2R, there is an optimum cell design and operating photovoltage that is not at the maximum power point (unlike water splitting) due to the selectivity dependence on potential. Using a continuum model of PEC CO2R, we will explore the co-design of the photoelectrode bandgaps and device architecture for the generation of C2+ products. The simulation results demonstrate the critical importance of simultaneously engineering the photoelectrode and device design and operation in order to ensure the photovoltage and photocurrent from the photoelectrode enables operation at the optimum potential. Finally, for PEC CO2R, we will explore the use of metal-insulator-semiconductor (MIS) structures to obtain high rates of CO2R. This includes both theoretical and experimental investigations that elucidate the controlling phenomena and when coupled with the ionomer films provide high rates of direct PEC CO2R. Overall, the insights between the photoelectrode and device design is critical for the design of monolithic, unassisted PEC CO2R systems that yield high STC2+ efficiency.
Acknowledgements
This material is based partially 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 and a University of California grant.
(Invited) High-Rate CO2 Reduction Reactions: From Electrocatalysts to Gas-Diffusion Electrodes
Authors: Kamiya Kazuhide 
Published: February 2024

Excessive emissions of carbon dioxide (CO2) from the use of fossil fuels are becoming a serious obstacle to the sustainable development of society. Electrochemical CO2 reduction (CO2RR) into value-added products using solar electricity is a promising technology to close the carbon cycle and sequester anthropogenic CO2 into chemical feedstocks.[1] The practical implementation of CO2RR requires a high current density, as the current density for CO2RR is directly correlated to the capital cost of the electrodes and electrochemical cells. The use of gas diffusion electrodes (GDEs) effectively accelerates CO2RR by overcoming the mass transport limitation due to the inherently low diffusion and solubility of CO2 in water. This presentation summarises our recent studies on high-rate CO2RR from the point of view of both novel electrocatalyst designs and appropriate electrode assembly.
Single-atom electrocatalysts (SAECs), consisting of single isolated metal sites dispersed on heterogeneous supports, are one of the promising electrocatalysts for high-rate gaseous CO2RR. We have employed various single metal-doped covalent triazine frameworks (M-CTFs) as a platform for CO2RR electrocatalysts on GDEs and systematically investigated them to derive sophisticated design principles using a combined computational and experimental approach.[2-4] The Ni-CTF exhibited both high selectivity and high reaction rate for CO production. In contrast, the Sn-CTF exhibited selective formic acid production, and the faradaic efficiencies (FEs) and partial current density reached 85% and 150 mA/cm2, respectively.[2] These results were in close agreement with the intermediate CO2RR adsorption strength obtained by DFT calculations.
In addition to the synthesis of efficient electrocatalysts, the triple phase boundary (TPB) at the GDE, where the catalyst material, electrolyte, and gas pores intersect, needs to be enlarged for high-rate gaseous CO2RR.[5,6] We successfully increased the partial current density for multicarbon products (C2+) over cupric oxide (CuO) nanoparticles on gas diffusion electrodes in neutral electrolytes to a record value of 1.7 A/cm2 by maximizing the area of the CO2RR active interface.[5] In particular, we demonstrated that the thickness of catalyst layers was one highly sensitive factor in determining the maximum current density for C2+. Although the GDE and electrocatalyst used in this case are not unique, the optimized assembly elicits their undermined potential.
[1] K. Kamiya, Nakanishi* et al. Chem. Lett. 2021, 50, 166-179.
[2] S. Kato, K. Kamiya* et al. Chem. Sci., 2023, 14, 613–620.
[3] P. Su, K. Kamiya*et al. , Chem. Sci., 2018, 9, 3941-3947.
[4] K. Kamiya* Chem. Sci. 2020, 11, 8339–8349.
[5] A. Inoue, K. Kamiya* et al. EES Catal. 2023, 1, 9-16.
[6] T. Liu*, K. Kamiya* et al. Small 2022, 18, 2205323.
(Invited) Towards Broadband Photocatalysis
Authors: Ma Dongling 
Published: February 2024

Forming nanomaterials junctions and using plasmons represent two important, promising strategies for realizing broadband photocalysis in strategically important applications such as solar fuels and photocatalytic degradation of pollutants. In this talk, I will present some of our recent work on the rational design of nanohybrids and their applications in solar fuels and photocatalysis. One example is about the in situ synthesis of plasmonic Ag nanoparticles (AgNPs) and Ag-MOF. The intimate and stable interface between the AgNPs and Ag-MOF and hot electron transfer from the plasmonic AgNPs to MOF led to highly efficient visible-light photocatalytic H2 generation in aqueous solution, which surpasses most of reported MOF-based photocatalytic systems. This work sheds light on effective electronic and energy bridging between plasmonic NPs and MOF.
References: [1] Nature communications, 12: 1231 (2021); [2] Nature communications, 2023, in press; [3] Chemistry of Materials, 2021, 33, 695-705; [4] Adv. Funct. Mater. 2019, 1902486.
Unintended Cation Crossover in CO2 Conversion MEA Cells: Causes and Effects
Authors: El-Nagar Gumaa , Haun Flora , Gupta Siddharth , Stojkovikj Sasho , Mayer Matthew T. 
Published: February 2024

Membrane electrode assemblies in gas diffusion cells enable CO2 reduction at industrially relevant rates, yet their long-term operational stability is often limited by the formation of solid precipitates (e.g. K2CO3) in the cathode pores. This is a consequence of a combination of 1) local alkalization due to the electrochemical reaction, 2) generation of (bi)carbonate by chemical reaction of CO2 with the alkaline electrolyte, and 3) the presence of alkali metal cations. In catholyte-free, zero-gap cells using anion exchange membranes, the presence of electrolyte cations at the cathode is the result of unintended crossover from the anolyte, and a detailed understanding of the factors enabling this crossover is lacking. Here we show that the anolyte concentration governs the flux of cation migration through the membrane, and this substantially influences the behaviors of copper catalysts in catholyte-free CO2 electrolysers. Systematic variation of the anolyte ionic strength (using aqueous KOH or KHCO3) correlated with drastic changes in the observed product selectivity – most notably, at low ionic strength, Cu catalysts produced predominantly CO, in contrast to the mixture of C2+ products typically observed on Cu. In this talk, we examine the factors influencing ion crossover and the resulting effects on catalyst structure and activity, under conditions of both CO2 and CO reduction. Operando X-ray absorption spectroscopy and quasi in situ X-ray photoelectron spectroscopy were used to study how the catalyst is affected by operation conditions. Our results show that even in catholyte-free cells, cation effects (including unintended ones) can significantly influence reaction pathways, and this must be considered in future development of catalysts and devices.
El-Nagar, G. A., Haun, F., Gupta, S., Stojkovikj, S. & Mayer, M. T. Unintended cation crossover influences CO2 reduction activity in Cu-based zero-gap electrolysers. Nature Communications14, 2062 (2023) doi: doi.org/10.1038/s41467-023-37520-x

Figure 1
Manganese-Based Tunnel and Layered Oxide Cathodes for Secondary Alkali-Ion Batteries
Authors: Yadav Jaya , Vanam Sai Pranav , Senthilkumar Baskar , Amonpattaratkit Penphitcha , Barpanda Prabeer 
Published: February 2024

Designing new cathode materials remains crucial in developing (post) Li-ion batteries. Mn-based oxide cathodes have received wide attention due to their sustainable nature, low cost, elemental abundance, structural diversity/polymorphism, and rich oxidation states (2+ to 7+), offering tunable redox potential [1]. Here, we have investigated different oxide-based cathode insertion compounds for secondary metal-ion batteries.
i) We have demonstrated tunnel-type sodium insertion material Na44MnO2(NMO) as an intercalation host for Li-ion and K-ion batteries. The solution combustion synthesized Na0.44MnO2 assuming an orthorhombic structure (space group Pbam), exhibited rod-like morphology. After electrochemical ion exchange from NMO, we obtained Na0.11K0.27MnO2 (NKMO) and Na0.18Li0.51MnO2 (NLMO) cathodes for K-ion batteries and Li-ion batteries, respectively [2]. These new compositions, NKMO and NLMO, showed excellent cycling stability with capacities of ∼74 and 141 mAh g–1 (first cycle, C/20 current rate). The underlying mechanistic features concerning charge storage and structural modifications in these cathode compositions were probed by combining ex-situ structural, spectroscopy, and electrochemical tools [3].
ii) Using composite formation, we have tried to improve the P2-type layered material. Here, the stable Na7(Li1/18Mn1/18Ni3/18Fe2/18χ1/18)O2–xNa2MoO4 biphasic composite was synthesized using Mo doping. Overall, the redox chemistry was investigated using various spectroscopy techniques to prove the net capacity resulted from both cationic and anionic redox reactions [4].

Keywords: energy storage; batteries; cathode; manganese oxides; intercalation; doping

References:

[1] N. O. Vitoriano et al., T. Rojo, Energy Environ. Sci. 2017, 10 (5), 1051−1074.
[2] K. Sada, B. Senthilkumar, P. Barpanda, Chem. Commun. 2017, 53 (61), 8588−8591.
[3] S.P. Vanam et al., P. Barpanda, Inorg. Chem. 2022, 61 (9), 3959−3969.
[4] S.P. Vanam, P. Barpanda, Electrochim. Acta. 2022, 431, 141122.
SO2-Tolerant Electrocatalytic Reduction of CO2 from Simulated Industrial Flue Gas
Authors: Papangelakis Panagiotis , Miao Rui Kai , Lu Ruihu , Ozden Adnan , Liu Shijie , Sun Ning , O'Brien Colin P. , Hu Yongfeng , Shakouri Mohsen , Xiao Qunfeng , Li Mengsha , Khatir Behrooz , Huang Jianan Erick , Wang Yakun , Xiao Yurou Celine , Li Feng , Shayesteh Ali , Zhang Qiang , Liu Pengyu , Liu Hanqi , Golovin Kevin , Howe Jane , Wang Ziyun , Li Jun , Sargent Edward H. , Sinton David 
Published: February 2024

The electrochemical reduction of CO2 using copper-based electrocatalysts offers a route to produce high-value multicarbon (C2+) products from renewable electricity (Nat. Catal. 4, 952-958 (2021); Nature 614, 262-269 (2023)). To date, the efficient electrocatalytic conversion of CO2 to multicarbon products has only been possible when using impurity-free CO2 sources, such as from direct air capture. The generation of such high-grade CO2 streams is expensive, accounting for almost half of the total energy required for both capture and electroreduction processes (Nat. Catal. 4, 952-958 (2021)). Conversely, capturing CO2 from point sources, such as industrial flue gas, is more efficient due to the higher concentration of CO2 in the feed. However, trace amounts of sulfur dioxide (10 ~ 400 ppm SO2) inherently present in these streams will significantly degrade the CO2 conversion process. All previous attempts to convert CO2 with SO2 present in the feed have resulted in immediate catalyst poisoning and an irreversible loss of CO2 conversion activity.
In this study, we designed a modified catalyst layer to react a stream of dilute CO2 containing 400 ppm SO2 to multicarbon products with high stability and performance metrics that match or exceed those achieved with pure CO2 streams. Driven by density function theory and COMSOL simulations, we designed an ionomer:copper:polytetrafluoroethylene (PTFE) (ICP) electrode that features both hydrophobic and highly-charged hydrophilic domains to limit water adsorption and promote CO2 over SO2 transport near the electrochemically active sites. This deactivates the SO2 poisoning mechanism, thus enabling stable and efficient CO2 conversion (see figure). Our approach achieved a sustained C2+ Faradaic efficiency (FE) of 50% for the initial 160 hours at 100 mA cm-2.
In order to improve the overall C2+ current efficiency (jC2+) towards industrial scales, we applied our strategy in high-surface-area copper electrodes. We achieved CO2 conversion in the presence of 400 ppm SO2 with a C2+ FE of 76% at a current density of 700 mA cm-2, surpassing what can be achieved in existing integrated CO2 capture-electrolysis systems that use pure CO2. Overall, our approach provides a fully 140-fold increase in performance (FEC2+ × jC2+) compared to the best prior CO2 conversion systems with added SO2 (Nat. Nanotechnol. doi: 10.1038/s41565-022-01286-y (2023); J. Am. Chem. Soc. 141, 9902-9909 (2019)). These findings represent an important advancement in the field of CO2 conversion and highlight the potential of our strategy for industrial-scale applications.

Figure 1
Structural Tuning Strategy to Improve Ionic Conductivity of Eco, Cost-Effective Zr-Based Halide Solid Electrolyte
Authors: Noh Joohyeon , Kang Kisuk 
Published: February 2024

Lithium-ion conductors based on halide anion frameworks have garnered significant attention as optimal ceramic conductors for composite cathodes due to their high oxidation stability and deformability. Recently, a cost-effective halide electrolyte, Li2ZrCl6, has been reported as a promising alternative to rare-metal-based halide solid electrolytes which are not suitable for manufacturing. Despite the economic advantage of using Zr, its ionic conductivity remains relatively low (0.36 mS cm-1), which could limit its applicability in high C-rate applications.
To enhance the ionic conductivity of Zr-based solid electrolytes, various structural tuning strategies have been employed. However, challenges persist, such as unstable cycling due to the redox reactions of metal ion and the uneconomical aspects of incorporating rare metals like Yttrium, Indium, and Lanthanides. In this study, we propose economical and rational strategies for tuning Li2ZrCl6 to achieve higher ionic conductivity without compromising stability and affordability.
By introducing zero-valent dopants, vacancies, we were able to increase the ionic conductivity of the Zr-based solid electrolyte to nearly twice its original value (0.8 mS cm-1). Our detailed analysis reveals that the enhanced conductivity and reduced activation energy are primarily due to the activation of local diffusion paths, resulting from the alleviated repulsion between transition metal ions and Lithium ions. Furthermore, we establish the relationship between the Lithium-ion content and Li diffusivity in the Zr-based solid electrolyte, uncovering a new aspect for structural tuning in Zr-based solid electrolytes.
Consequently, we optimized the content of Lithium ions and dopants in the solid electrolyte, synthesizing a super-ionic conductive Zr-based solid electrolyte with an impressive ionic conductivity of approximately 1.6 mS cm-1 and highest Zr percentage reported to date. Our findings offer a rational and economical design strategy for developing stable hcp-LZC structures with faster ionic conduction. This breakthrough has the potential to facilitate the widespread adoption of Zr-based solid electrolytes in lithium-ion batteries.
Nafion-Based Quasi-Solid-State Polymer Electrolyte for Lithium-Sulfur Batteries
Authors: Gerle Martina , Sievert Brigitta , Lufrano Ernestino , Nicotera Isabella , Friedrich K. Andreas , Nojabaee Maryam 
Published: February 2024

Lithium-sulfur batteries are considered a strong contender for next-generation high-energy battery systems given their high gravimetric energy density. However, this battery chemistry is still facing challenges such as the polysulfide shuttle effect caused by the high solubility of long-chain lithium polysulfides (Li2Sn) resulting in active material loss and compromised cycle life. Solid-state polymer electrolytes (SPEs) represent a promising pathway to address this issue by preventing the formation and transport of these undesirable polysulfide intermediates.1,2 Moreover, the application of flexible polymer electrolytes promotes safe high energy batteries for smart textiles.
In this study, single lithium-ion conducting solid polymer electrolytes (SLIC-SPEs) based on lithiated Nafion membrane have been investigated, utilizing the chemical and thermal stability of this kind of ionomers. Among others, a mixture of ethylene carbonate (EC) and propylene carbonate (PC) was tested as organic aprotic swelling solvent offering advantageous characteristics such as great chemical stability and high ion mobility while avoiding phase separation issues and undesired leaching.
Sulfur-infiltrated ultramicroporous carbon composite cathodes were utilized in combination with the investigated SLIC-SPEs, facilitating a quasi-solid-state lithium-sulfur full cell with carbonate-solvent compatibility and high active material utilization.3

Electrochemical performance of the full cell was investigated elaborately and compared with a reference system using solely the liquid EC:PC solvent. While rapid capacity fading can be observed for the liquid electrolyte cell, an enduring high capacity is found in the lithiated-Nafion system. For better understanding of these effects, cycling analysis was accompanied by implementing impedance spectroscopy upon galvanostatic cycling. The electrochemical characterization indicates the formation of a stable film and high degree of reversibility during cycling of the lithiated-Nafion cell whereas an increased film resistance due to sulfur cross-over and electrolyte decomposition was observed within the liquid electrolyte system.
(1) Z. Li, W. Lu, N. Zhang, Q. Pan, Y. Chen, G. Xu, D. Zeng, Y. Zhang, W. Cai, M. Yang, J. Mater. Chem. A
2018,
6 (29), 14330-14338.
(2) X. Hao, H. Wenren, X. Wang, X. Xia, J. Tu, J. Colloid Interface sci.
2020,
558, 145-154,
(3) M. Nojabaee, B. Sievert, M. Schwan, J. Schettler, F. Warth, N. Wagner, B. Milow, K. A. Friedrich, J. Mater. Chem. A
2021,
9 (10), 6508-6519,
An Improved Lithium-Sulfur Battery By Using Porous Carbon As the Sulfur Template
Authors: HAN Jinseok , Kim Jae-Kwang 
Published: February 2024

As global demand for electric vehicles (EVs) continues to rise, the rechargeable battery of high-energy density is actively researched. Lithium-ion batteries (LIBs) have been widely used in the electric vehicles (EVs) and have been leading the EVs market. However, LIBs have reached their limits due to their practical low-capacity and high-cost. Therefore, novel strategy is required to solve the problem of the LIBs.
Lithium-sulfur (Li-S) batteries attract attention because of high theoretical capacity (1675 mAh/g) and high energy density (2600 Wh/kg). Moreover, sulfur as electrode material is abundant and inexpensive. However, the sulfur-based batteries have serious disadvantages, which is the shuttle of intermediate polysulfides (Li2Sn, 2<n≤8), and low conductivity, result in poor cycle stability and low discharge capacity [1,2].
Therefore, in this study, the sulfur electrode is fabricated by impregnating sulfur into three-dimensional porous carbon. The porous structure suppressed the dissolution/shuttle of sulfur species and improved the cycling stability and discharge capacity. Moreover, three types of porous carbon templated of activated carbon cloth, activated carbon felt, and porous carbon foam were compared on electrochemical performances.
Reference

Jimin Yun, 2023, High Loading Sulfur Cathode with Three-dimensional Porous Current Collector for Lithium-Sulfur Battery, Department of Materials Engineering and Convergence Technology, Gyeongsang National University, P.11, p.14

Kimin Park, 2022, Design od metal phosphate based electrodes for high-performance Li-Ion & Li-S battery, Department of materials science and engineering seoul national university, P.1
Ptve-Impregnated 3-Dimensional Porous Carbon for High-Properties Organic Battery
Authors: Kim Chae Kyoung , KIM Hye Jung , Kim Jae-Kwang 
Published: February 2024

Lithium-ion batteries are the most common type because their operating potential and energy density are both higher than those of other rechargeable batteries. However, the associated electrochemical reaction involves the intercalation and deintercalation of the lithium transition-metal-containing electrodes. The constituent transition-metals of lithium-ion batteries, such as cobalt, nickel, manganese, and lithium are limited resources, the cost of which is increasing as the market expands. Therefore, organic electrode materials are gaining an increased level of attention as possible replacements for lithium transition-metal-based electrode materials. The use of organic materials would enable the design of metal-free batteries. In addition to the potential low-cost and ease of scalability, the structural diversity of organic molecules would allow the tailoring of both the physical and electrochemical properties of the electrode materials, thus offering excellent opportunities for constructing sustainable and environmentally friendly power sources and energy-storage systems. However, they present some serious issues, a high self-discharge as a result of the dissolution of organic active materials into the organic liquid electrolyte and the content of large amounts of carbon conductor material into the electrode due to the intrinsic low electrical conductivity of the organic active materials.
In this study, to overcome these disadvantages, 3-Dimensional porous carbon have been applied to composite with poly(2,2,6,6-tetramethylpiperidine-N-oxyl-4-vinyl ether) (PTVE) organic electrode material. The use of the PTVE-impregnated porous carbon electrode structure enhanced the contents of active material and electrochemical performance.