bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Functionalization of Mesoporous Silica Enabling Long-Life Lithium-Sulfur Batteries
Authors: Ryoo San Deul , Kim Hye Ran , Shim Jae Rin , Jung Yongju
Published: November 2022

Lithium-sulfur (Li-S) batteries have been regarded as future-generation of energy storage systems due to potential merits of their high energy density and natural abundance of sulfur cathode material. However, their practical applications are significantly limited by poor cycle life, which arises from the highly soluble polysulfide species in the organic electrolyte solution. The dissolved polysulfide ions diffuse toward the lithium anode and are converted to inactive materials on the surface of lithium metal. To tackle this issue, mesoporous material such as ordered mesoporous silica (OMS) has been applied as an additive. However, it is found to be an ineffective polysulfide reservoir, where the cathode undergoes great capacity loss on cycling. In this study, a carbon-coated OMS (c-OMS) is synthesized through selective polymerization on the surface of the mesopores followed by carbonization. The effect of c-OMS additive was examined in coin type cells containing a sulfur composite cathode. The conducting feature of c-OMS is found to effectively enhance the cycling stability of the sulfur cathode.
Thermal Stability of Active Materials Versus Different Type of Electrolytes
Authors: Hsu Hungjen , Lu Yushi , Ünal Mahir , Körber Nico , Chang Hansen , Frey Martin , Garche Jürgen
Published: November 2022

The safety of Lithium ion battery (LIB) is recently a hot topic due to their increased use by the electric vehicles. Energy density has become more and more important to solve the range anxiety. However, thermal behavior becomes more unstable due to this increase in energy density. Several studies have claimed that the main reason batteries have thermal runaway events are the reactions between the intercalated lithium in the anode and the liquid electrolytes [1] [2]. Therefore, solid state electrolytes are proposed [3] [4] to be an option to increase the thermal stability of LIBs.

In this work, thermal evaluation of Solid state battery materials will first be defined by a differential scanning calorimeter to understand the thermal stability of the different materials that might be used in different types of solid state cells. Materials tested include layered oxide cathodes with different Ni content, pure lithium metal and several types of solid electrolytes such as sulfides, polymers and oxides. Heat flow test with different combinations of the materials, such as cathode with anode, cathode with electrolytes and anode with electrolytes were conducted to isolate reaction mechanisms between the different materials. The results show, that compared to the thermal runaway paths of cell with liquid electrolytes, sulfide and oxide electrolytes show the possibility of improved thermal stability. However, polymer electrolytes might have the similar, or even worse, thermal behavior as liquid electrolytes.

Reference

[1] Ren, X. Feng, L. Liu, H. Hsu, L. Lu, L. Wang, X. He and M. Ouyang. "Investigating the relationship between internal short circuit and thermal runaway of lithium-ion batteries under thermal abuse condition." Energy Storage Materials, 2021.

[2]Mukai, T. Inoue and K. "Are All-Solid-State Lithium-Ion Batteries Really Safe?−Verification by Differential Scanning Calorimetry with an All-Inclusive Microcell." ACS Applied Materials & Interfaces, 2016.

[3]Chen, A. M. Nolan, J. Lu, J. Wang, X. Yu, Y. Mo, L. Chen, X. Huang and H. Li. "The Thermal Stability of Lithium Solid Electrolytes with Metallic Lithium." Joule, 2020.

[4]Feng, M. Ouyang, X. Liu, L. Lu, Y. Xia and X. He. "Thermal runaway mechanism of lithium ion battery for electric vehicles: A review." Energy Storage Materials, 2018.

Figure 1
Investigation of Transition Metal Oxide Post-Spinels for Calcium-Ion Batteries
Authors: Chando Paul , Shellhamar Jacob , Wall Elizabeth , Hosein Ian
Published: November 2022

The dependence on lithium for rising global energy demand coupled with the scarcity of lithium necessitates the exploration of post-lithium strategies. Calcium-ion batteries are one such post-lithium strategy that can mitigate rising costs owing to calcium’s natural abundancy. A critical gap in this field is the lack of cathodes capable of intercalating calcium at high voltages and capacities while also retaining structural stability. The handful of candidates evaluated thus far have been plagued by low capacities and poor cycling performance due to intercalation–induced phase changes and instability. Transition metal oxide post–spinel–type materials have been identified as potential candidates for reversible Ca–ion storage owing to their crystal structures and high theoretical energy densities. However, experimental validation of these theoretical predictions remains largely unaddressed. In this work, post-spinel Calcium Iron Oxide (CaFe2O4) and Calcium Manganese Oxide (CaMn2O4) are explored as cathodes for calcium-ion batteries. The redox activity of each cathode is investigated using galvanostatic (GS) cycling while their structural stabilities are evaluated with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The use of GS in tandem with XRD and SEM provides insights into the evolution of crystal structure with Ca–ion–transport within each cathode. Our results reveal that these post–spinel systems can cycle with a reversible capacity of 56 mAh/g, making them promising cathode candidates for Ca–ion batteries and warrant further investigation.
Highly Reversible Zn Metal Anode Enabled by Sustainable Hydroxyl Chemistry
Authors: Ma Lin , Vatamanu Jenel , Hahn Nathan T , Pollard Travis , Schroeder Marshall , Petkov Valeri , Ding Michael , Ren Yang , Luo Chao , Allen Jan L , Wang Chunsheng , Xu Kang
Published: November 2022

Enhancing Zn anode reversibility with sustainable chemistries is urgent for unlocking rechargeable Zn metal battery technology to complement Li-ion batteries and meet the growing demand for sustainable energy storage. However, conventional practices in electrolyte design which address anode irreversibility through altering the Zn2+ solvation shell often rely on costly concentrated chemicals1-2.

In this work, we demonstrate a sustainable and cost-effective electrolyte design strategy by using methanol as a solvent exemplar. The designed electrolyte exhibits unprecedented Zn reversibility combined with high depth of discharge (Coulombic efficiency (CE) >99.5% with 50% Zn utilization and a dendrite-free behavior >1800h) at 25°C due to the determinant interphasial chemistries enabled by the hydroxyl group. Moreover, the Zn anode also shows a high CE >99.5% with 20% Zn utilization at -40°C when supported by a desirable electrolyte bulk transport property. Excellent performance is demonstrated in the Zn || metal-free organic cathode full cells in a wide temperature range. The microscopic characterization and modeling identify the mechanism of unique interphase chemistry and its functionalities as the key factors responsible for dictating reversible Zn chemistry.

Reference

E. Blanc, D. Kundu, L. F. Nazar, Joule
2020, 4, 771–799.

Ma, M. A. Schroeder, O. Borodin, T. P. Pollard, M. S. Ding, C. Wang, K. Xu, Nature Energy
2020, 5, 743-749.
Effect of Solid-Electrolyte Pellet Density on Failure of Solid-State Batteries
Authors: Tu Howard Qingsong , Ceder Gerbrand
Published: November 2022

In this presentation, we will provide insight into the most prevalent failure mechanisms of solid-state batteries and correlates it with the relative density of the solid electrolyte pellet. We show that Li dendrites can be suppressed only when the relative density of the solid electrolyte pellet is beyond a threshold value of ~95%. Before this threshold value, the battery shorts easer if the pellet is denser due to faster Li dendrites growth within the percolating pores in the pellet. Detailed characterizations with FIB-SEM tomography and permeability test are employed to quantify the microstructural properties (such as pore size, connectivity, porosity and tortuosity) of the LPS pellet made at different relative densities. Our modeling results reveal the growth details of the Li filament inside pores with size ranging from 0.2 μm to 2 μm. The findings in this paper will greatly help understand the failure modes of solid-state batteries and advise the design strategies for the dendrite-free solid-state battery system.
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
Role of Mechanics-Driven Kinetic Interactions in Electrodeposition Stability
Authors: Singla Aditya , Naik Kaustubh Girish , Vishnugopi Bairav Sabarish , Mukherjee Partha P.
Published: November 2022

Solid-state batteries (SSBs) show a promise to boost energy density, power density and thermal safety of lithium-ion batteries. Even though solid electrolytes (SEs), owing to their mechanical rigidity, have enabled the use of Li-metal anodes, growth of filaments within the SE still remains a major challenge. Internal stresses and molar volumes of interacting species strongly influence both reaction kinetics at the anode-SE interface and ionic transport within the SE and thus, play an important role in dictating the stability of the solid-solid interfaces during electrodeposition. In this work, we examine the role of mechanics in altering the underlying reaction and transport processes by analyzing various electrochemical and mechanical parameters involved such as molar volumes, shear moduli, applied current density and ionic conductivity. We present a non-dimensional formulation to demarcate regimes of stable/unstable growth. The effects of interface morphology and molar volume variation at the interface have also been studied.
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).
Investigating Electrochemical Properties and Interfaces of the Non-Halogen Mg Electrolytes
Authors: Fan Shengqi , Cora Saida , Sa Niya
Published: November 2022

Rechargeable magnesium batteries are one of the most promising multivalent energy storage batteries due to high volumetric capacity, high abundance in the earth’s crust and low cost. Electrolyte development plays an essential role for the Mg battery design. Due to the lack of suitable Mg electrolytes that can be compatible with high voltage cathodes limited the commercialization of the rechargeable Mg batteries, the development of the halogen-free Mg-based electrolytes has received considerable attention and achieved significant advancements in recent years. In this study, our goal is to investigate the electrochemical properties and reaction mechanisms for the reversible Mg plating/stripping electrolytes in the non-halogen Mg electrolytes, which are strikingly impacted by solid electrolyte interphase (SEI) at the Mg electrolyte/electrode interface. This work might help to understand and overcome the challenges of the Mg anode-electrolyte compatibility issues.
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
Electrolyte Deprotonation Stimulates Phase Transition of Ni-Rich Cathodes in Na-Ion Batteries
Authors: Zheng Yu , Balbuena Perla B.
Published: November 2022

Sodium-ion batteries (SIBs) are considered as a promising alternative to lithium-ion batteries (LIBs), Since they are composed of naturally abundant elements, cheaper and larger scale battery modules can be assembled. However, due to their similar electrochemical mechanisms, their practical utilization is hindered by high reactivity of conventional carbonate electrolytes with electrode materials leading to the capacity fading over repeated charging cycles. To overcome this obstacle, localized high concentration electrolytes (LHCEs) are used as an effective approach to maintain localized solvation structure of active electrolyte salts by using hydrofluoroether as diluents. Earlier studies are mainly focusing on the interactions between electrolytes with anode materials. Little was known about the electrochemical reactions of LHCEs on SIB cathode. In this work, we examined the reactivities of carbonate electrolytes and LHCEs on NaNiO2 surfaces. Ab initio molecular dynamics simulations showed that carbonate electrolytes involve more dehydrogenation reactions than LHCEs. The proton-transfer reactions between electrolyte molecules and cathode surface oxygens cause the formation of hydroxyl (-OH) groups, which leads to reduction of neighboring surface nickel atoms from Ni3+ to Ni2+. As cathode surface gets desodiated, more proton-transfer reactions were observed and Ni migrations from transition metal layer to Na layer were also identified. Consequently, it results in the oxygen loss of NaNiO2 which accelerates the layered-rock salt phase transition of bulk cathodes.
Highly Conductive PEO-Based Polymer Composite Electrolyte for Na Battery Applications
Authors: Lu Xiaochuan
Published: November 2022

State-of-the-art Li- or Na-ion batteries typically use organic solvents in the electrolytes, which might cause serious safety issues. Replacing the liquid electrolytes with nonflammable, dense solid-state electrolytes can potentially solve this problem. Among all types of solid electrolytes, PEO-based polymer electrolytes (PBPEs) have attracted great attentions due to their excellent flexibility, chemical stability, and easiness for processing. In this talk, we will present our recent progress in development of flexible, Na-ion conducting PBPEs. In particular, we tried to incorporate various amounts of ionic liquid (i.e., PY14FSI) into PEO + NaFSI electrolytes that can increase the amount of amorphous phase in the polymer and thus achieve higher ionic conduction. It was found that the highest conductivity was achieved with the composition of P(EO)20NaFSI + 2.4PY14FSI (2 x 10-3 and 3 x 10-4 S cm-1 at 60oC and RT with a Na+ transference number of ~0.1). We further verified the performance of the electrolyte with a composition of P(EO)20NaFSI + 1.6PY14FSI in symmetric and full cells. The critical current density of the electrolyte in Na symmetric cells was as high as 0.5 mA/cm2 at 60oC and the cells also showed an excellent stability during ~700 cycles at a current density of 0.1 mA/cm2. A full cell with Na3V2(PO4)3 as the cathode showed an initial capacity of 100 mAh/g-1 and a Coulombic Efficiency of ~94%. All of these demonstrated a PBPE with excellent chemical, mechanical, and electrochemical performance and properties for Na battery application.

Figure 1
Development and Optimization of Composite Cathode Materials for Use with Thin-Film Glassy Solid Electrolytes in Solid-State Batteries
Authors: Fettkether Will , Martin Steve , Wheaton Jacob
Published: November 2022

The electrochemical properties and thermal behavior of thin-film glassy solid electrolytes (GSE) in the [Li2S - SiS2 - LiPO3] system make them viable candidates for inclusion in solid-state batteries. To properly assess these electrolytes in the full-cell format, compatible composite cathode materials must be developed. These materials must be electronically and ionically conductive, and form a stable interface in contact with the GSE. A composite blend of redox-active lithium iron phosphate (LiFePO4), a mixed-oxy-sulfide glassy electrolyte, carbon nanotubes, a lithium solvate ionic liquid (SIL), and styrene butadiene rubber binder (SBR) was utilized to create the cathode material. Mixing time and order of component mixing were controlled in order to optimize for ionic and electronic conductivities within the bulk composite powder. With the addition of the SIL and SBR, a composite cathode blend capable of stably cycling in contact with the GSE was created.
(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.
Investigation on Tethered Anion Effects in Solid Polymer Electrolytes for Li-Ion Batteries
Authors: Engler Anthony , Park Habin , Madhira Manas , Picca Dominic , Hanus James , Liu Nian , Kohl Paul
Published: November 2022

Solid polymer electrolytes (SPEs) have been proposed to reduce concentration polarizations within batteries by immobilizing anions to the polymer matrix, which can help stabilize the electrodeposition process and extend Li-ion battery lifetime. Unfortunately, single-ion conducting SPEs continue to suffer from poor conductivity due to coupling with the slow segmental mobility of polymer chains and poor ion pair dissociation. Our group systematically investigated how different tethered anions affect the Li-ion conduction and polymer segmental mobility. Copolymers were synthesized using a common neutral monomer, poly(ethylene glycol) methyl ether methacrylate (PEGMA), with a series of different anionic monomers: 4-styrene sulfonate, 4-styrene phosphonate, 4-styrene TFSI, and methacrylate TFSI. These monomers presented a series of anions of varying strength with the same styrene structure, sulfonate vs. phosphonate vs. TFSI, as well as exploring structural monomer changes for the same TFSI anion, styrene vs. methacrylate, that allows for systematic changing of polymer electrolyte properties. Each copolymer series was further expanded by changing the composition of neutral-to-anionic monomers, ranging from 10-67 mol% anionic. The increased ion exchange capacity of the phosphonate groups led to a high degree of ion aggregation that exhibited hard mechanical properties and very low Li-ion conductivities. Increasing the electron delocalization of the ions from sulfonate to TFSI greatly improved the conductivities and lowered activation energies of ion transport, with methacrylate being slightly better than styrene. Implications of these results will be discussed for next-generation polymer electrolyte design.
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
Heterogeneity-Driven Interface Instability in Solid-State Batteries
Authors: Vishnugopi Bairav Sabarish , Naik Kaustubh Girish , Mukherjee Partha P.
Published: November 2022

While solid-state batteries promise to enhance the energy density and power density of conventional lithium-ion batteries, the morphological instability of the lithium metal anode persists to be a major challenge. During plating and stripping, the dynamic evolution of the lithium metal-solid electrolyte interface is governed by a coupled set of electrochemical-mechanical-transport processes. This mechanistic interaction is influenced by several factors including the mechanical properties of the solid electrolyte and lithium, presence of heterogeneities such as grain boundaries, defects and voids, and external pressure/temperature. In this presentation, the underlying role of microstructural and interfacial heterogeneities on the reaction kinetics, morphological growth, and the origin of electrochemical-mechanical failure will be examined. A fundamental analysis on how such heterogeneity-driven implications scale with plating and stripping currents, and their mechanistic dependence on the interfacial stress-temperature fields will be presented.
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.
Mechanisms of Lithium-Ion Transport in Solid-State Electrolyte and Cathode Materials Prepared By PVD
Authors: Fitzgerald Kelsey , Numan-Al-Mobin Abu , Kustas Frank , Smirnova Alevtina
Published: November 2022

Conventional liquid-state lithium-ion batteries are currently limited in their energy density, lifetime, thermal stability, and safety. The design of viable solid-state batteries shows promise to improve upon the shortcomings of liquid cells. Removal of organic electrolytes increases the lifetime while making these batteries more environmentally friendly and safe. Solid-state batteries also have the potential to demonstrate higher energy density and provide ultrafast charging. However, these desirable properties require significant efforts to uncover and utilize the chemical, morphological, and electrochemical properties of solid-state electrolytes and cathode nanocomposites. This study addresses physical vapor deposition (PVD) technology for design of solid-state material architectures with the properties needed to create high-performance electrochemical cells. The PVD process allows cathodes and electrolytes to be deposited as dense films, thereby increasing their energy density and electrochemical performance. Furthermore, this process results in excellent adhesion between dissimilar materials allowing for increased electrical and ionic conductivity. This work uses lithium oxyhalide electrolytes and eco-friendly lithium iron phosphate cathodes, which were both deposited in vacuum using radio frequency power and magnetron sputtering sources. A co-deposition technique was used to successfully deposit thin film layers of cathode, electrolyte, cathode/electrolyte mixture, and carbon thin films in a single process. Electrochemical cells with different functional layers deposited by PVD (~7 mm) were compared to the cells with commercial LFP cathodes (~32 mm thick). The electrochemical cells created by PVD showed lower charge transfer resistances and high electrochemical stability at ultra-high (10C) charging rates. Significant improvements in performance are expected to continue as the process is improved in terms of ionic and electronic transport at cathode-electrolyte interfaces. The authors acknowledge financial support from the DOD Navy SBIR Phase II project (N68335-18-C-0021), the NSF IUCRC program for supporting the “Center for solid-state electric power storage” (#2052631), and the South Dakota “Governor’s Research Center for electrochemical energy storage”.

Figure 1
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.
Magnetism to Engineer Electrocatalyst and Device Performances
Authors: Sreenivasan Sreeprasad T
Published: November 2022

Electrocatalytic devices such as fuel cells and redox flow batteries emerged as an appealing platform for renewable energy applications. The application of magnetic field to electrochemical systems, through diverse mechanisms, demonstrated good potential to enhance the efficacy of the energy-relevant electrocatalytic reactions. This talk will discuss some of our results in magnetic field-assisted enhancement in the electrocatalytic activity of molecular and network catalysts. The magnetic field-assisted enhancement in the performance of electrocatalytic devices and its fundamentals unraveled through a combined experimental-theoretical exploration and diverse microscopic and spectroscopic techniques, including electron spin resonance (ESR) spectroscopy, scanning electrochemical microscopy (SECM), and X-ray absorption spectroscopy (XAS), will be presented.
(High-Temperature Energy, Materials, & Processes Division J. B. Wagner, Jr. Young Investigator Award) Joule Heating Based Ultrafast High-Temperature Sintering for Materials Discovery and Manufacturing
Authors: Hu Liangbing
Published: November 2022

I will share my group’s research and development of electrified ultrahigh-temperature synthesis as a novel platform for discovering and manufacturing new energy and environmental materials. I will start with the design and fabrication of ultrahigh temperature heaters, followed by three specific research topics, including high entropy nanoparticles (Science 2018, 359, 1489, Cover), a high-performance battery membrane (Science 2020, 358, 521, Cover), and reactors with rapid programmable temperature for thermochemical reactions (Nature, 2022, CH4 pyrolysis and NH3 synthesis).

Figure 1
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.
Solid Oxide Fuel Cells with 3D Inkjet Printing Modified LSM-YSZ Interface
Authors: Tian Jiashen , Dou Yan , Nian Qiong , Milcarek Ryan J
Published: November 2022

Solid oxide fuel cells (SOFCs) have drawn attention as an alternative power generation technology due to demonstrated high efficiency and low emissions. The lanthanum strontium manganite (LSM)-yttria-stabilized zirconia (YSZ) cathode is utilized widely for SOFCs due to its high performance and stability. The electrochemical oxygen reduction reaction that occurs in the cathode can be enhanced by the porous LSM-YSZ cathode with good electronic and ionic conductivity. With sufficient electrochemically active reaction sites, the oxygen ion transfer processes in the mixed ionic conductor (YSZ) and at the interface of cathode and electrolyte (LSM-YSZ) become critical for the activity of the cathode. Thus, the pillar shape YSZ microstructure with ~ 150 μm×150 μm×10 μm (L×W×H) size can be fabricated by 3D inkjet printing on the interface of electrolyte and cathode to increase the TPB area and enhance the connection between the dense YSZ electrolyte and mixed YSZ ionic conductor. Scanning Electron Microscopy (SEM) is utilized to assess the morphology and microstructure of the YSZ interface. To investigate the influence of the modified interface on the performance of the SOFC, electrochemical performance testing and characterization are conducted for the SOFCs with/without the modified YSZ layer. The microstructures with different pillar central spacing are also fabricated by 3D inkjet printer to optimize the geometry of the LSM-YSZ interface.