bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting Fuel Cell Ink Aggregation
Authors: Srivastav Harsh , Weber Adam Z. , Radke Clayton J. 
Published: November 2022

Polymer-electrolyte fuel cells (PEFCs) provide multisector decarbonization solutions including in transportation, manufacturing, and long-term energy storage. They have become increasingly popular in these areas due to their high efficiency, power density, and low (or zero) emissions compared to traditional fossil-fuel dependent processes. The PEFC catalyst layer is the most complex and key part of the cell, and is critical for optimizing PEFC performance. Several studies have explored the structure/function relationships of PEFC catalyst layers, yet the physics and interactions controlling its in-situ formation remain a mystery. PEFC catalyst layers are traditionally fabricated out of a catalyst supported on a carbon nanoparticle with an ionomer, traditionally perfluorosulfonic acids (PFSAs) such as Nafion, as a binder, which stabilizes the carbon suspensions in the ink dispersion. Recent studies demonstrated the importance of pH as an experimental parameter for both comparison and characterization of such systems.1

In this talk, we explore the interactions in the colloidal inks through detailed mathematical modeling. We propose a kinetics-based model representing species aggregation with pointwise interacting spheres that vary in charge through buried side chains for predicting the aggregation behavior of Nafion and carbon in solutions under varying conditions, such as solvent, Nafion wt% and carbon wt%. To demonstrate the accuracy and robustness of the model, we compare the results against a range of pH conditions and size distributions. The insights from the model help establish design criteria and guide future ink and process conditions.
Acknowledgements
This study was conducted under the Million Miles Fuel Cell Truck Consortium (M2FCT) funded by the Hydrogen and Fuel Cell Technologies Office in the Energy Efficiency and Renewable Energy Office of the U.S. Department of Energy under contract DE-AC02-05CH11231.
References

S. A. Berlinger, B. D. McCloskey, and A. Z. Weber, J. Phys. Chem. B, 122, 7790–7796 (2018).
Oxygen Reduction Reaction on Fe-N-C Catalysts: A Computational Spectroscopy Study
Authors: Gallenkamp Charlotte , Ni Lingmei , Krewald Vera , Kramm Ulrike I. 
Published: November 2022

The oxygen reduction reaction (ORR) plays an important role in proton exchange fuel cells (PEFCs). In PEFCs, ORR is the cathodic half-cell reaction complementary to the oxidation of the fuel, but since ORR has slow kinetics, it requires high amounts of catalyst. State-of-the-art ORR catalysts are based on the expensive metal platinum. Even though the amount of platinum needed for ORR in PEFCs has been reduced significantly over the last decade, it is still the major contributor to the cost of PEFCs, thus hindering the commercialization and accessibility of this technology.[1]
Iron and nitrogen doped carbon (Fe-N-C) catalysts have gained a lot of research attention due to their high ORR activity, which makes them potential substitutes for platinum-based catalysts. In Fe-N-C catalysts, iron is thought to be atomically dispersed as pseudo-molecular active centres with four- or fivefold nitrogen coordination spheres which are embedded in graphene layers. Since Fe-N-C catalysts are typically prepared via pyrolysis, they have a highly amorphous structure and can contain multiple iron phases, which makes them difficult to characterize structurally and spectroscopically. Consequently, there is still a scientific debate on the exact nature of the active site, in terms of iron spin and oxidation states and its precise coordination environment.[2-4]
Fe-57 Mössbauer spectroscopy can provide direct insights on iron spin and oxidation states and is used successfully to characterise the amorphous Fe-N-C catalysts. Until recently, the interpretation of Mössbauer spectra was limited to comparisons with small reference complexes which lack the extended π-systems of Fe-N-C catalysts.[2] Since synthesis of such extended π-systems as references is difficult, we have developed a library of computational models that encompasses different structural motifs and electronic structures. With increasing use of in situ and operando experiments on Fe-N-C catalysts, the interest in computational models for the interpretation of experimental Mössbauer spectra has grown.[4-6] In this contribution, we present our density functional theory results for different molecular Fe-N-C models with extended π-systems and discuss their electronic structures and spectroscopic properties.
[1] L. Osmieri, et al. Current Opinion in Electrochemistry
2021, 25, 100627.
[2] U. I. Kramm, et al. Advanced Materials
2019, 31, 1805623.
[3] S. Wagner, et al. Angewandte Chemie International Edition
2019, 58, 10486.
[4] L. Ni, C. Gallenkamp, et al. Advanced Energy & Sustainability Research
2021, 2, 2000064.
[5] J. Li, et al. Nature Catalysis, 2021, 4, 10.
[6] X. Liu, et al. Chem
2020, 6, 3440.
Elucidating Activity-Stability Trade-Off to Design Highly Durable Fe-N-C Catalysts
Authors: Zeng Yachao , Li Chenzhao , Zachman Michael J. , Cullen David A. , Xie Jian , Myers Deborah J. , Wu Gang 
Published: November 2022

In this work, we developed a Fe2O3@ZIF-8 composite precursors and combined with a novel thermal activation treatment under an Ar/H2 mixture atmosphere (i.e., forming gas), which successfully prepares a highly active Fe-N-C catalyst. 57Fe Mossbauer spectroscopy analysis experimentally verified that the catalyst only contains S1 sites. The highly active Fe-N-C catalyst achieved exceptional ORR initial activity in acids, exceeding that of a Pt/C baseline catalyst (60 µgPt cm−2) in rotating disk electrode (RDE) tests. The MEA tests further verified that the Fe-N-C catalyst's activity is competitive with Pt/C cathode (0.1 mgPt cm−2) in the kinetic range. Notably, the catalyst demonstrated remarkable activity of 50.8 mA cm−2 (@0.9 ViR-free) under H2-O2 conditions, exceed the U.S. DOE target. As expected, the catalyst degraded significantly during the stability ASTs.
To increase S1 sites and address the stability issues, we further developed in-situ CVD methods to treat Fe2O3@ZIF-8 precursors under forming gas flow but with additional N/C precursors that was put at the upstream sides of the tube furnace. Therefore, additional nitrogen and carbon sources are added to the Fe2O3@ZIF-8 precursors during the thermal activation of catalysts. As a results, we can populate the intrinsically stable S2 sites to design highly durable Fe-N-C catalyst. The resulting catalyst presented outstanding stability in both RDE and fuel cell tests. The E
1/2 gained 21 mV after 100,000 cycles of accelerated degradation test (ADT), achieving 0.869 VRHE at the end of the test, which is close to Pt/C (60 µgPt cm−2) in acid electrolyte. The current density of MEA at 0.8 V retained unchanged, and the peak power density increased from 454.0 to 512.0 mW cm−2 in H2-fuel cell after 30,000 cycles of AST.
(Invited) Durability and Accelerated Aging of Anion-Conducting Membranes and Ionomers
Authors: Nellithala Dheeraj , Shah Parin , Kohl Paul 
Published: November 2022

Low-temperature, polymer-based fuel cells and water electrolyzers using anion conductive polymers have several potential advantages over acid-based polymer electrolyzers. However, the long-term durability of the ion conducting polymer has not been investigated to the same extent as proton conducting polymers. Further, accelerated aging test conditions with known acceleration factors have not been developed.
In this study, a family of poly(norbornene) polymers used in fuel cells and electrolyzers was aged under a variety of conditions to determine the aging rate and acceleration factors. In particular, the relationship between temperature, alkalinity, and time were investigated.
Electrode Potential Influences The Reversibility of Lithium Metal Anodes
Authors: Ko Seongjae , Obukata Tomohiro , Shimada Tatau , Takenaka Norio , Nakayama Masanobu , Yamada Yuki , Yamada Atsuo 
Published: November 2022

Li-metal batteries are considered an ultimate energy-storage device since a Li metal anode presents high capacity and low redox potential.1 However, a poor Coulombic efficiency (CE) during a plating/stripping of Li metal, has hampered their commercialization. To overcome this issue, a diverse type of electrolytes, which forms a robust solid electrolyte interphase (SEI) on the Li-metal surface, has been introduced over the past decade.2 However, a correlation between the CE and SEI chemistry is still vague since it is mostly established on the basis of indirect experimental methodologies. Indeed, a huge change in CEs has been reported even in the presence of similar functional-SEIs, indicating that there is another essential factor that governs the CE.3

Fundamentally, the redox potential of Li metal is located far outside the thermodynamic potential window of organic electrolytes, thus inevitably inducing reductive degradation of the electrolyte. Importantly, the Li metal is known as a quasi-reference electrode, which indicates its redox potential strongly depends on the chemical potential of Li+ in the electrolyte. Thus, if the redox potential of Li metal is upshifted to narrow the gap from the potential window of the electrolyte, the CE should be increased with thermodynamically mitigated electrolyte decomposition.
Based on this assumption, the Li redox potential (V vs. electrolyte-independent redox system, ferrocene Fc/Fc+) was evaluated and plotted versus the average CEs of Li plating/stripping reactions in 74 different electrolytes. The result presents that the average CE is increased as an increase of the redox potential of Li metal that varies over 0.6 V depending on the electrolytes, demonstrating that the degree of the reductive degradation of electrolyte is governed by the redox potential of Li metal in the given electrolyte. The mechanism behind the redox potential variation of Li metal was studied with both machine-learning analysis and Raman spectroscopy. Obviously, the coordination states of Li+ and FSI- shows a high relevance for the Li redox potential. Specifically, as an increase of Li+-FSI- ion-pairing, the redox potential of Li metal is upshifted gradually.
In conclusion, we postulate that a large variation of Li electrode potential (>0.6 V), which is deeply linked to the coordination condition of Li+ and FSI- in the electrolyte, is a simple yet overlooked ‘hidden factor’ that dominates Li-metal battery performance. This rationale will provide a new chance to design a stable Li-metal batteries.
Reference
1. D. Lin et al., Nat. Nanotechnol., 12, 194–206 (2017).
2. S.C. Kim et al., J. Am. Chem. Soc., 143, 18703−18713 (2021).
3. G. M. Hobold et al., Nat. Energy, 6, 951–960 (2021).
Mechanistic Understanding of Lithium Plating/Stripping Processes on the 3D Conductive Host Based on Vertically Aligned Carbon Nanofibers for Li Metal Anode
Authors: Rajendran Sabari , Li Jun 
Published: November 2022

The highest theoretical capacity (3860 mAh/g) and lowest redox potential (-3.04 V vs standard hydrogen electrode) makes lithium metal as a promising anode for next generation high energy density batteries.1 Despite theoretical advantages, there are challenges in commercializing Li metal anodes such as low coulombic efficiency, dendrite formation and poor cycling life. Dendrite formation can cause short circuit and thermal runaway, which is a safety concern. Among the various ways to mitigate the Li dendrite formation, using three-dimensional (3D) current collectors with lithiophilic properties and low tortuous pore architecture is an effective way. It would decrease the local current density owing to high active surface area while accommodating the large volume change during prolonged charge/discharge cycles.
Vertically aligned carbon nanofibers (VACNF) have been demonstrated as a promising candidate as a lithiophilic 3D host for lithium metal anodes as they possess unique conically stacked lithiophilic graphitic edges with O containing functional groups and high N doping (~6.5 at%).2 However, a fundamental, deeper understanding of the Li plating/stripping processes on such 3D electrodes has not been developed yet. Here in, we investigate the lithium nucleation and growth processes and its morphological changes using ex-situ structural characterization techniques such as SEM and cryo-TEM. The composition of the solid electrolyte interface is investigated using XPS. In-situ Raman spectroscopic studies provided further information about the changes that occur in the VACNFs during Li plating/stripping processes and Li intercalation/deintercalation processes. Ion-beam sputtering of an ultrathin gold layer onto the VACNFs was found to further improve the lithiophilicity of the 3D electrode and lead to more reversible Li metal plating/stripping. The new insights on the electrodeposition of lithium in 3D electrodes and its relationship with the enhanced cycle life acquired using various analytical tools will be discussed.
Reference:
(1) Manthiram, A.; Chung, S.-H.; Zu, C. Lithium–Sulfur Batteries: Progress and Prospects. Advanced Materials
2015, 27 (12), 1980–2006.
(2) Chen, Y.; Elangovan, A.; Zeng, D.; Zhang, Y.; Ke, H.; Li, J.; Sun, Y.; Cheng, H. Vertically Aligned Carbon Nanofibers on Cu Foil as a 3D Current Collector for Reversible Li Plating/Stripping toward High-Performance Li–S Batteries. Advanced Functional Materials
2020, 30 (4), 1906444.
Electrochemical-Mechanical Coupling at Li Metal / Solid Electrolyte Interfaces and the Safety of Li Metal Solid-State Batteries
Authors: Albertus Paul , Johnson Nathan B , Bhargava Bhuvsmita , Song Yueming , Carmona Eric A , Larson Karl 
Published: November 2022

Using Li and Na metal with a solid electrolyte in high-energy and safe batteries for consumer applications is of great interest, but our understanding of the behavior of this interface, as well as the expected safety of high-energy cells built with Li or Na metal and a solid electrolyte, requires improvement. In this talk I will describe (1) our work in both modeling and measuring electrochemical-mechanical coupling at a Li or Na metal / solid electrolyte interface, as well as (2) modeling and experimental work on Li metal solid state battery safety.
The electrochemical-mechanical coupling topic (1) will focus on the influence on the current distribution of expected mechanical loadings at a metal/solid electrolyte influence, taking into account the expected plastic deformation of the metal electrode. We find that the mechanical boundary conditions, and inclusion of plastic deformation of a metal electrode such as Na or Li, strongly influences the resulting impact on the interfacial current distribution. Our approach and recent experimental work for parameterizing and validating electrochemical-mechanical coupling will also be presented. Here, we focus on interfacial characterization and methods to study thin films of solid state battery materials under well-defined mechanical loads.
The solid-state battery topic (2) will focus on a quantitative understanding of temperature rise in Li metal solid state batteries, based on the thermochemistry of the reactions that occur upon heating due to an external source (e.g., an oven test) or an internal short. Previously reported differential scanning calorimetry experiments as well as those we collect provide heat flows vs. temperature for the reactions among cell components (e.g., Li metal, cathode powder, solid electrolyte, cathode binder and conductive additive, current collectors). This data serves as a basis for modeling temperature rise in large-format cells. We find that oxygen release from metal oxide cathodes that reacts with molten Li in the cell can drive significant temperature rise, and discuss methods to improve the safety of Li metal solid state batteries.
High-Energy and Long-Lasting Lithium Metal Batteries Employing Garnet-Type Solid Electrolytes with Tailored Lithium Metal Compatibility
Authors: Kim Sewon , Kim Jusik , Im Dongmin , Kang Kisuk 
Published: November 2022

One of the viable options to significantly augment the energy density of lithium-ion batteries (LIBs) is to adopt lithium metal anode in the cell, which offers the highest theoretical capacity (3,860 mAh g-1) among anode materials.1 However, the practical obstacles such as dendrite growth, low Coulombic efficiency, and safety issues still remain unresolved, despite the extensive efforts to employ the lithium metal anode in LIBs.2 Recent progress in solid-state electrolyte development has granted a new promising opportunity for the utilization of lithium metal anodes, whose mechanical rigidity and non-flammable nature are supposed to effectively suppress lithium dendrite short-circuiting, thereby securing battery safety. Nevertheless, there has been no report thus far that demonstrates acceptable levels of electrochemical performance of solid-state lithium metal batteries for real-world applications.3,4

In our research, a lithium-metal-battery employing tailored garnet-type Li7-xLa3-aZr2-bO12 (LLZO) solid-electrolytes that can meet the lifespan requirements of both electric vehicles and stationary applications has been achieved, affording remarkable stability and energy density over 2,000 cycles. It is demonstrated that the compatibility between LLZO and lithium metal is crucial for the long-term stability, which can be accomplished by regulating bulk dopants and the corresponding dopant-specific interfacial treatment using protonation/etching. The appropriate selection of dopant and dopant-specific protonation/etching agent for LLZO leads to (i) the formation of a stable passivation layer at the interface with lithium metal, (ii) effective release of residual stress in LLZO, and (iii) intact contact at the interface.
The lithium-metal cell with 2 mAh cm-2 cathode (12 mg cm-2) delivers a cumulative capacity of over 4,000 mAh cm-2 at 3 mA cm-2, which to the best of our knowledge, is the highest long-term cycle value reported for lithium metal batteries with LLZO electrolytes. Moreover, even with the thin 110-µm-LLZO electrolyte and 20-µm lithium metal, a high-loading-capacity cell (3.2 mAh cm-2) exhibits a superior cycle life (>600 cycles) at 2 mA cm-2 without short-circuiting, affording a basis for the high-energy-cell design with ultra-thin electrolyte. In addition, an all-solid-state-battery, excluding the ionic liquid electrolyte, was successfully demonstrated using the composite cathode, which could cycle over 1,000 times at a high current density of 3 mA cm-2 without short-circuiting. To the best of our knowledge, this is the first all-solid-state battery that can operate over 1,000 cycles, enabled by the garnet-type electrolytes and cathode with a commercially acceptable capacity.
These findings are expected to open a new avenue for developing long-lasting solid-state lithium metal batteries by highlighting the efficacy of the coupled bulk and interface doping of solid electrolytes.
Structural Analysis of LiCoPO4 Electrode/Nasicon-Type Li1.3Al0.3Ti1.7(PO4)3 Solid Electrolyte Interface
Authors: Ichihara Fumihiko , Niitsu Kodai , Miyoshi Shogo , Mitsuishi Kazutaka , Masuda Takuya 
Published: November 2022

All-solid-state lithium-ion batteries (ASSLIBs) with oxide-based solid electrolytes are a promising candidate for next generation of rechargeable batteries, due to their reliability and high-energy density. The formation of well-defined electrode/solid electrolyte interfaces with an excellent ionic conductivity by co-sintering is one of the key challenges to develop oxide-based ASSLIBs.1 Electrode materials and solid electrolytes often react with each other to form a resistive substance at their interface during co-sintering.2-4 Thus, optimization of the co-sintering conditions is important to control the interfacial structure which governs the ionic conductivity. However, the effect of the interfacial structure on the ionic conductivity remains unclear.
In this study, we co-sintered the composites of LiCoPO4 (LCP) electrode material and Li1.3Al0.3Ti1.7(PO4)3 (LATP) oxide-based solid electrolyte and investigated the interfacial structure by using X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and scanning transmission electron microscopy combined with electron energy loss spectroscopy and an energy-dispersive X-ray spectroscopy (STEM-EELS/EDX).
Figure 1(a) shows the XRD patterns of the LCP/LATP composites before and after sintering at 800°C. The diffraction patterns are almost identical to each other and all the diffraction peaks are attributed to the LCP and LATP with an exception of AlPO4 impurity. However, the Co K-edge XANES is slightly changed after sintering as shown in Figure 1(b). These results suggest that a small amount of LCP and LATP react with each other. Figure 1(c) shows a typical STEM image of the LCP/LATP composites after sintering at 800°C. According to EDX analysis, light and dark gray domains correspond to LCP and LATP, respectively. Apart from LCP and LATP, there are two types of LCP/LATP interfaces: interface A and B. Line profile STEM-EELS/EDX analysis revealed that LCP and LATP directly bound to each other at the interface A. On the other hand, a thermally reacted thin layer, possibly cobalt oxide (CoO) and/or cobalt phosphide (Co2P), is formed at interface B. The effect of such thermally reacted interlayer on the ionic conductivity will be discussed in detail.
References:

R. Chen, Q. Li, X. Yu, L. Chen and H. Li, Chemical Reviews, 2020, 120, 6820-6877.

M. Gellert, E. Dashjav, D. Grüner, Q. Ma and F. Tietz, Ionics, 2017, 24, 1001-1006.

C.-Y. Yu, J. Choi, V. Anandan and J.-H. Kim, The Journal of Physical Chemistry C, 2020, 124, 14963-14971.

L. Miara, A. Windmuller, C. L. Tsai, W. D. Richards, Q. Ma, S. Uhlenbruck, O. Guillon and G. Ceder, ACS Applied Materials and Interfaces, 2016, 8, 26842-26850.

Figure 1
Antimony Telluride Nanocomposite As a High Performance Anode for Rechargeable Potassium-Ion Batteries
Authors: Verma Rakesh , Moon Chae-Eun , Park Chan-Jin 
Published: November 2022

The development of high-capacity and low-cost energy storage systems are a top priority in electric vehicles and smart grids. Room temperature potassium-ion batteries (PIBs), which have the advantages of high theoretical capacity, abundant earth reserves, and low potassium costs, have recently emerged as an appealing alternative to traditional lithium-ion batteries (LIBs). In particular, finding advanced anode materials with suitable operation potential and high capacity is of significance for next-generation PIBs. In this regard, Sb-based materials have recently gained popularity as promising anode materials for batteries in terms of their suitable working potential, high density, and theoretical capacity. Among them, Sb2Te3 has a much higher density (6.66 g/cm3) than other Sb-based materials such as Sb2O3, Sb2S3, and Sb2Se3. This suggests that Sb2Te3 can have a high theoretical capacity. In addition, Te exhibits a higher conductivity than S or Se. Accordingly, the Sb2Te3 is appealing as an ideal anode for PIBs. Unfortunately, the Sb2Se3 has poor cycling stability and rate performances, which is primarily owing to the large volume change during alloying and dealloying.
In this study, using a simple hydrothermal strategy, we synthesized a carbon-coated Sb2Te3 nanocomposite (Sb2Te3@C). In the novel design, the Sb2Te3@C nanocomposite is compactly encapsulated by a uniform carbon layer, which effectively relieves structural stress leading to preventing structural pulverization and stabilize the solid electrolyte interface layer. As expected with this optimal design, the Sb2Te3@C nanocomposite electrode performed nicely suitable for PIBs. In addition, the effect of the alloying/dealloying process on the crystal structure of Sb2Te3@C was investigated using in- situ/ex-situ XRD patterns recorded at various stages of discharge and charge to clarify the alloying mechanism. Furthermore, a full cell made up of a Sb2Te3@C anode and a potassium Prussian blue type cathode also exhibited successful operation.