bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactivity of VC Electrolyte at Li-Metal Electrode: New Insights on SEI Initial Formation from Density Functional Embedding Theory
Authors: Pavone Michele , Fasulo Francesca , Munoz Garcia Ana Belen 
Published: November 2022

The metallic lithium (Li) represents the most promising anode material among the next generation of solid-state lithium batteries [1]. An efficient strategy to achieve durable and effective Li-anode batteries is by engineering the solid-electrolyte interphase (SEI) with purposely designed molecules.
To this aim, the vinylene carbonate (VC) is one of the most used additives in conventional electrolytes. Some recent experiments proved that the VC promotes the formation of a stable and protective SEI layer between Li metal and electrolyte [2, 3]. Unless the well-known SEI composition, it is difficult to control the VC reactivity, that involves dissociation and polymerization at the electrode surface. Therefore, to dissect these tangled processes, here we present new atomistic insights on VC-Lithium SEI formation via first-principles calculations by Density Functional Embedding Theory (DFET) [4, 5]. Such approach has potentialities for modeling complex reactions at hybrid interfaces in electrocatalysis: it is well suited to combine the best feasible approaches for molecular species (in this case, hybrid HF-DFT for VC molecules and derivatives) and for Li metal electrode (semi-local GGA density functional).
Our results highlight different VC dissociation pathways, with formation of reactive radical species and localized cluster of Li2O and Li2CO3. The use of hybrid-DFT-in-DFT embedding is crucial for obtaning energy barriers and qualtitative results in agreement with experiments [3]. Overall, the energetics and structural features of these intermediates improve the current understanding of SEI formation process and can be exploited to drive the reactions toward the desired interfacial properties.
[1] J. Janek, W. G. Zeier, Nat Energy 1 (2016) 16141.
[2] A. L. Michan et al. Chem. Mater. 28 (2016) 8149.
[3] Y. Kamikawa, K. Amezawa, K. Terada, J. Phys.
Chem. C 124 (2020) 19937
[4] C. Huang, M. Pavone, E. A. Carter, J. Chem. Phys. 134 (2011) 154110
[5] C. Huang, A.B. Muñoz-García, M. Pavone, J. Chem. Phys. 145 (2016) 244103
Optimizing the Design of Anode-Free Sodium Batteries Using Machine Learning Methods
Authors: Zohair Murtaza , Thelen Adam , Jiao Weimin , Hu Chao , Pint Cary L. 
Published: November 2022

The anode-free sodium battery has been demonstrated as a practical next-generation battery due to (1) the electrochemical stability of Na metal in standard electrolytes, (2) comparable or greater energy density than commercial Li-ion, and (3) the ability to leverage standard industrial Li-ion manufacturing techniques to scale production [1-2]. However, a key challenge in this system centers on the design of a thin coating, called a nucleation layer, on the negative terminal current collector that guides the reversible nucleation and growth of sodium metal. Whereas researchers have highlighted Coulombic efficiencies exceeding 99.9% with sodium metal, understanding and controlling this heterogeneous nucleation process is a critical barrier to the practical design of stable, high performance sodium batteries. In this work, we discuss our efforts in using a Bayesian optimization algorithm to accelerate the search for the optimal properties of a thin nucleation layer in a sodium metal half-cell to optimize anode-free cell performance. Using this sequential design approach, we are able to quickly and concurrently optimize multiple interacting properties of the nucleation layer that affect reversible sodium deposition, such as carbon material composition, oxygen content, and surface area to yield a best performing architecture for an anode-free sodium cell. Further, I will also discuss the important role of pressure on the nucleation and growth of sodium metal, emphasizing the need for better understanding at the interface between mechanics and electrochemistry for anode-free lithium and sodium cells.

References

[1] A.P. Cohn, N. Muralidharan, R. Carter, K. Share, and C.L. Pint, “Anode-free sodium battery through in situ plating of sodium metal,” Nano Lett. 17, 1296 – 1301 (2017).
[2] A.P. Cohn, T. Metke, J. Donohue, N. Muralidharan, K. Share, and C.L. Pint, “Rethinking sodium-ion anodes as nucleation layers for anode-free batteries,” J. Mater. Chem. A 6, 23875 – 23884 (2018).
Two-Dimensional Mixed Lead/Bismuth Oxychloride Based Materials As Anodes for Sodium-Ion Batteries
Authors: Ahuja Vinita , Singh Subham , V Rishikesh , Senguttuvan Premkumar 
Published: November 2022

The continuous pursuit on building low cost and sustainable batteries to efficiently harvest renewable energy from intermittent sources is ever expanding. The research on Na-ion technology has gained significant interest due to inexpensive and broad availability of precursor materials. Until now, various Na-ion anodes including carbonaceous materials such hard carbon, alloy-based materials such as Bi, Pb, Sb and Sn based systems and conversion materials have been explored1. Along this line, the recent chase on two dimensional (2D) materials such as chalcogenides, MXenes and van der Waals types oxyhalide heterostructures, have become more intense due to their excellent electrical and structural properties 2. Among them, 2D Sillén-type metal oxyhalide heterostructures (MOX), due to their unique layered structure consisting of anionic sheets interleaved with cationic layers have gain particular interest as electrode materials. BiOCl is one such candidate with fluorite-like layers, [Bi2O2]2+ intergrown with halide Cl– anions, have been studied as anode in rechargeable batteries. However, its application is mainly challenged by rapid capacity decay originating from particle pulverization and unstable solid electrolyte interphase (SEI).
In this work, 2D layered mixed lead bismuth oxychloride nanosheets (BiOCl4 and PbBiO2Cl 3) were synthesized by new rapid room temperature chemical precipitation route. In former anode, the electrolyte engineering approach has been used to enhance the cycling stability of BiOCl and at the same time, its electrochemical (de)sodiation mechanism is also clarified through in-operando XRD studies, which reveals the reversible formation of Bi ↔ NaBi ↔ cubic-Na3Bi phases. On the other hand, the later anode, i.e., 2D-PbBiO2Cl was further investigated with the combined in-operando XRD and ex-situ TEM, XPS studies, which reveal a distinct (de)sodiation process of the 2D-PbBiO2Cl in comparison with reported Na-(Pb/Bi) phase diagram. This 2D heterostructure demonstrated stable sodium storage performance (~250 mAh g–1 for 250 cycles at 100 mA g–1). Henceforth, the detailed understanding of formation process of these two structures (BiOCl and PbBiO2Cl) at room temperature using material characterizations and electrochemical studies combined with operando findings will be discussed to comprehend the reversible storage mechanism of 2D-MOX type heterostructures as anodes in SIBs.
References:

Y. Hwang, S.T. Myung, Y.K. Sun, Chem. Soc. Rev. 2017, 46, 3529–3614.

Zeng, Y. Xiao, J. Liu, K. Yang, L. Fu, Chem. Rev. 2018, 118, 6236–6296.

Ahuja, S. Singh, R. Vengarathody, P. Senguttuvan, J. Phys. Chem. C 2021, 125, 17622

Ahuja, S. Singh, R. Vengarathody, P. Senguttuvan, J. Power Sources 2022, 529, 231227
(Invited) Phosphoric Acid Redistribution in HT-Pemfcs: Scratching the Surface
Authors: Kim Yu Seung , Lim Katie , Matanovic Ivana , Maurya Sandip , De Castro Emory 
Published: November 2022

There is a growing consensus that electrochemical energy conversion of hydrogen and high-energy-density fuels will be essential in the global transition towards a sustainable energy future. High-temperature proton exchange membrane fuel cells (HT-PEMFCs) that use doped phosphoric acid can operate above 100 °C under anhydrous conditions and provide an ideal solution for heat rejection in automotive fuel cell applications. An imperative but poorly understood research area of HT-PEMFCs is phosphoric acid redistribution in the membrane electrode assembly (MEA). While the phosphoric acid redistribution during pre-conditioning in MEAs improves fuel cell performance, further acid redistribution can be detrimental to the lifetime of the fuel cells.
Here, we present our recent discovery regarding phosphoric acid redistribution in phosphoric acid doped membrane-based HT-PEMFCs. We first show the phosphoric acid concentration change in polybenzimidazole-based MEAs under various operating conditions. This result explains more than 10,000 hours of stable operation for HT-PEMFCs under certain operating conditions. Next, we investigate the phosphoric acid redistribution behavior in the MEA by calculating the energetics of phosphoric acid clusters in the membrane and electrodes, emphasizing the importance of phosphoric acid retention in the membrane. Lastly, we explain how acid redistribution can be controlled by introducing ion-pair coordinated membranes, providing future directions for obtaining more durable HT-PEMFCs for various applications.
Controlling the Morphology of Electrodeposited Lithium Metal Via Seeded Growth: Stepwise Spherial to Fibrous Lithium Growth
Authors: Park Se Hwan , Lee Yun Jung 
Published: November 2022

Lithium metal has been gained intense research interest because of its high specific capacity and lowest electrochemical potential for next generation battery systems with high energy density. However, the utilization of Li metal as an anode material has been limited due to the uncontrolled Li deposition and side reactions on Li metal surface that induce low coulombic efficiency, poor cycle performance and safety issues. Controlling morphology of electrodeposited Li metal is one major direction to resolve these issues. Identification of Li deposition mechanism governing the morphology evolution is prerequisite for establishing strategy for controlling morphology. Herein, we explore governing deposition mechanism from the morphology evolution at varied current (0.2- 1.8 mA cm-2) and suggest a strategy for growing low surface area Li fibers.
We found that fibrous Li growth follows the initial spherical Li particle formation when the Li sphere size reaches the critical value. The diameter of the initially formed Li particles decreases with the current density. Initially formed spherical Li particles at a low current density (0.2 mA cm-2) are sufficiently large to grow with a fibrous morphology. Thus, the spherical particles evolve to fibrous Li during subsequent growth. On the other hand, at a higher current density, the Li particles are initially smaller than the critical size and thus cannot immediately grow into a fibrous morphology. Spherical growth of the existing Li particles and additional nucleation on the current collector surface continue, resulting in multilayer Li particles. After Li particles reach the critical size, Li can grow with a fibrous form. Due to the preferential deposition on the existing fibrous Li, the morphology of spherical Li particles smaller than the critical size does not change. Therefore, only fibrous Li deposits were formed at low current density (0.2 mA cm-2), but both spherical and fibrous Li deposits were formed at higher current densities.
Based on the morphology evolution mechanism, seeded Li deposition strategy was proposed to minimize the surface area of Li deposits and improve cycling stability of Li metal electrode. The stepwise spherical to fibrous Li growth was achieved by changing the current from low to high (0.2 to 1.8 mA cm-2). Li deposits morphology was well controlled by this strategy resulting in all fibrous morphology with smooth surface. The Li deposits of seeded growth strategy achieved smaller surface area, suppressed side reactions and improved cycle life more than four times compared to that of constant current deposition with same average current density (1 mA cm-2).

Figure 1
Li Morphology Evolution during Initial Cycling in a Gel Composite Electrolyte
Authors: Tsai Wan-Yu , Chen Xi , Kalnaus Sergiy , Sahore Ritu , Westover Andrew S 
Published: November 2022

Li metal anodes are the potential solution for high-energy batteries. One of the challenges of applying such a high-energy anode is Li dendrite growth, which results in short-circuit and thermal runaway. Current battery research focuses on developing solid electrolytes to serve as a physical barrier to prevent dendrite growth. However, the Li morphology change during plating and stripping, and the mechanisms of how Li dendrite grows and propagates into a complex composite solid electrolyte are poorly understood. Understanding and controlling Li morphology evolution, dendrite formation, and growth during cycling are crucial to developing dendrite suppression strategies for solid electrolytes and enabling high-energy lithium metal batteries.
In this work, Li morphology evolution during initial cycling in a crosslinked PEO-based gel composite electrolyte full cell with NMC 811 cathode is monitored via post-mortem SEM. The results show that severe surface pitting occurs as early as the second stripping cycle. Pit formation and continuous dissolution is the main cause of Li surface roughening and dendrite growth mechanism in the model gel composite electrolyte. Comparing Li dendrite growth mechanisms in liquid, polymer, and solid electrolytes, the observed dendrite growth mechanism resembles that of the liquid electrolyte the most. This study suggests that strategies to improve the electrochemical reversibility of electrodeposited Li reported in liquid electrolytes to control Li morphology and prevent dendrite growth may be transferrable in a gel electrolyte.
This work is sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL), managed by UT-Battelle, LLC for the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. Part of the measurements was performed at the Center for Nanophase Materials Sciences (CNMS), which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences.
Polybenzimidazole Membrane for Vanadium Flow Battery Applications
Authors: Azizi Kobra , Hjuler Hans , Cleemann Lars Nilausen , Henkensmeier Dirk , Duburg Jacobus Cornelis , Gubler Lorenz 
Published: November 2022

The vanadium redox flow battery (VRFB) is one of the most promising secondary batteries as a large-capacity energy storage device for storing renewable energy.1 Perfluorinated-based ion exchange membranes such as Nafion are the most widely used membranes in VRFB due to their high proton conductivity. However, the extremely high cost and low ion selectivity of Nafion have limited their further application in VRFB. Among the aromatic hydrocarbon-based membranes that combine both high ion selectivity and high proton conductivity, polybenzimidazole- based membranes have served as one of the most promising alternatives to Nafion due to their excellent chemical and mechanical stability and low cost.2

In the present work m-PBI membranes of varying thickness and modified PBI were prepared, and their properties and VRFB performances were compared. The voltage efficiency (VE) increased with decreasing membrane thickness because of the decreasing ohmic resistance. The excellent current efficiency (CE) of VRFBs using meta-PBI based membranes is attributed to the negligible vanadium crossover observed in ex-situ permeability tests.
The stability of the membranes after long term cycling is one of the most challenging problems in large-scale VRB applications. The durability of PBI membrane in VRFB cell testing and the capacity decay was measured by operating the cells for 100 cycles under a high current density of 200 mA cm−2.

Fig 1: Flow battery efficiencies using electrodes: 2.5 mm SGL, CR = 20%, membrane: PBI 7 µm at current density of 200 mA/cm2, the electrolyte solution V(IV):V(III) (50:50) in 2.0 M H2SO4 and 0.05 M H3PO4 .

The chemical stability of PBI membranes was analyzed after immersion of the PBI samples in various highly oxidizing and reducing sulfuric acid based vanadium and cerium solutions. The membranes stayed unchanged for more than 4 months. This result suggests that the PBI membranes demonstrate excellent ex-situ chemical stability in the harsh acid, oxidizing and reducing conditions.
References:
1) Noh, M. Jung, D. Henkensmeier, S. W. Nam and Y. Kwon, ACS Appl. Mater. Interfaces, 9 (2017) 36799-36809.
2) Chen, H. Qi, T. Sun, C. Yan, Y. He, C. Kang, Z. Yuan, X. Li, J. Membr.
Sci., 586 (2019) 202-210.

Figure 1
Conjugated Bipolar Redox-Active Electrolyte for Symmetric Redox Flow Battery
Authors: Jadhav Rohit G. , Minteer Shelley D. 
Published: November 2022

Organic non-aqueous redox-flow batteries (O-NRFBs) are gaining traction as viable alternatives for long-term, low-cost stationary energy storage with a wide potential window.[1] The symmetric O-NRFBs with single bipolar electrochemically active molecule as both anolyte and catholyte (i.e. bipolar redoxmer) helps to mitigate permanent cross-contamination and capacity fading.[2] However, symmetric O-NRFBs with bipolar molecules are hampered by the scarcity of redox active molecules capable of serving as a stable bipolar redoxmer with high cell potential and unpredictable side reactions.[3] This study proposes the π-conjugation of electrochemical active electron donors and electron acceptor which leads to the possible control over direct electronic perturbation between acceptor-donor to form new type of redox molecules. This study aims designing of benzothiadiazole based conjugated bipolar redox-active molecule with high potential window and high stability.
[1]. M. Li, S. A. Odom, A. R. Pancoast, L. A. Robertson, T. P. Vaid, G. Agarwal, H. A. Doan, Y. Wang, T. M. Suduwella, S. R. Bheemireddy, R. H. Ewoldt, R. S. Assary, L. Zhang, M. S. Sigman, and S. D. Minteer, “Experimental protocols for studying organic non-aqueous redox flow batteries,” ACS Energy Lett., 2021, 6, 11, 3932–3943.
[2]. M. Li, J. Case, and S. D. Minteer, “Bipolar redox-active molecules in non-aqueous organic redox flow batteries: status and challenges,” ChemElectroChem, 2021, 8, 1215–123.
[3] M. Li, G. Agarwal, I. A. Shkrob, R. T. VanderLinden, J. Case, M. Prater, Z. Rhodes, R. S. Assary and S. D. Minteer, “Critical role of structural order in bipolar redox-active molecules for organic redox flow batteries,” J. Mater. Chem. A, 2021, 9, 23563-23573.
Manipulation of Anode Nanostructure and Composition By Glancing Angle Deposition for Thin-Film Solid Oxide Fuel Cells
Authors: Hwang Jaewon , Cha Suk Won 
Published: November 2022

Co-sputtering is a simple yet effective technique for fabricating a thin film of composite materials and different compositions by adjusting the electrical power of each sputtering target. However, practical issues arise when depositing cermet materials such as Ni-YSZ and Ni-GDC because of the contrasting characteristics of metal and ceramic sputtering targets. For example, the surface binding energy of GDC is significantly higher than that of Ni, resulting in a considerably lower sputtering yield of GDC. The difference in sputtering yield is further exacerbated by the low power density limit of the GDC target, which is set by its unfavorable material properties such as brittleness and low thermal conductivity. In contrast, due to its magnetic property, Ni requires sufficiently high sputtering power during magnetron sputtering.
This work combines co-sputtering with advanced sputtering techniques such as glancing angle deposition (GLAD) and oblique angle deposition (OAD) to fabricate otherwise unobtainable Ni-GDC anode microstructure with various compositions. Reduced flux capture area of Ni caused by the high incident angle of GLAD allowed control of thin-film compositions, and optimal composition was determined based on fuel cell performance and electrochemical impedance spectroscopy (EIS) analysis. A sufficient amount of GDC was necessary to expand the triple-phase boundary (TPB) and suppress the thermal agglomeration of highly mobile Ni.
The effect of electrode nanostructure on fuel cell performance was also investigated. The ballistic shadowing effect during OAD was utilized to produce thin-film electrodes with various porosities. With the increase of the deposition angle, the porosity increased, whereas the in-plane electrical conductivity decreased due to the reduced density. The columnar structure was also manipulated by managing the substrate position through azimuthal rotation. As a result, various columnar structures such as vertical posts, slanted posts, and zig-zag were fabricated, and the optimal microstructure was determined via electrochemical examinations.
Fabrication of AAO-Based Four-Stack Thin Film Solid Oxide Fuel Cells for the Low-Temperature Operation Using Sputtering Method
Authors: Kim Yang Jae , Cha Suk Won 
Published: November 2022

Anodic Aluminium Oxide (AAO) based four thin-film solid oxide fuel cell (TF-SOFC) stack was fabricated. The fuel cell stack was tested and analyzed at the low-temperature window. Since the low-temperature operation has many advantages, such as lowering the system cost and widening the material selection, there has been much effort to reduce conductive resistance, mainly at the electrolyte, which is the most problematic issue in low-temperature operation. One of the solutions is TF-SOFC deposited on the various substrates or supporting materials. AAO, a non-conductive and nanoporous substrate, has been widely used in fabricating TF-SOFC as a substrate because of its uniformly arranged pores and highly developed manufacturing process.
However, AAO is a poor template for stacking TF-SOFCs because it has lower mechanical strength than metal, has no electrical conductivity, and has a different coefficient of thermal expansion from metal. In this study, therefore, planarly stacked TF-SOFC were fabricated to expand its limits of use as a template for the stacked fuel cell. Nickel-based anode, yttria-stabilized zirconia (YSZ) electrolyte with functional layers, and platinum cathode and current collector were sequentially deposited using sputtering and atomic layer deposition methods. All thin-film components of four cells were deposited on the AAO at the same time, making good connections between each electrode. By effectively setting the deposition process, unnecessary pores of AAO were blocked, and current collecting layers were stably formed in between the structure of the cells with a step difference.
Then, the stacked TF-SOFC were electrochemically analyzed, including the current density-voltage-power density curve (i-V-P curve) and electrochemical impedance spectroscopy (EIS) being compared to a single cell. The microstructure of the fuel cell and its electrically connected structures were observed by scanning electron microscopy (SEM) and focused ion beam (FIB) cross-sectional SEM analyses. The cell’s overall voltage was comparable to four times that of a single cell, and the power density was obtained. We revealed the correlation between the electrochemical performance and the microstructure of individual cells and the whole stack. The full stack achieved electrochemical and mechanical stability by forming a complete fuel cell structure and enhanced the applicability of the planar cell stack on the AAO substrate.