bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Ionomer Gradients in Anode Catalyst Layers for Low Temperature PEM Water Electrolysis
Authors: Gollasch Marius , Harms Corinna , Wark Michael
Published: November 2022

Water electrolysis is a crucial technology for large-scale hydrogen generation, that is required for the transition to a fossil fuel-free energy system. Even though water electrolysis systems are already deployed in a limited capacity, the technology is largely constrained to liquid alkaline electrolysis. Proton exchange membrane (PEM) electrolysis could pose an alternative but it is still hindered by high investment costs, in-part due to its reliance on scarce noble-metal catalysts. Alternative structural designs of the anode catalyst layer (CL) could reduce Iridium loading of the whole system and thus accelerate its wide-spread application. In fuel cell research, it was already reported that a multi-layer design with varied ionomer content enhances performance of the CL and in-turn lowers required catalyst loading.[1,2,3]

In this study, a gradient design for ionomer content is employed for anode CLs for the application in PEM water electrolysis. CLs are coated in a stacked multi-layer design via ultrasonic spray coating of Iridium/Nafion® suspensions. The target ionomer loadings (10 and 30 wt.%) are confirmed by a combination of thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The coating process yields homogenously loaded reference CLs as well as through-plane graded CLs with the desired ionomer loading. Additionally, scanning electron microscopy (SEM) in conjunction with energy dispersive spectroscopy (EDS) shows equal CL thickness across all ionomer loadings and spatially differentiated Nafion® content throughout the CLs thickness. Electrochemical characterizations are carried out in an electrolysis-adapted gas diffusion electrode (GDE) half-cell setup to allow for quick examination and prototyping of produced layers. Differences in electrochemical performance of these layers can be observed with one gradient design CL showing reduced overpotential across all current densities compared to the homogenous CLs. In-particular a high ionomer loading near the membrane improves performance, most likely due to increased proton conduction to the membrane and higher available pore volume near the porous transport layer.

Further analysis is performed on electrochemical studies to deepen the understanding of the role of ionomer in anodic PEM water electrolysis CLs. Particularly, the investigation of protonic and electric conductivity through the CL is of interest, because this parameter is most influenced by ionomer loading.[4]

References:

[1] Y. Wang, T. Liu, H. Sun, H. Wie, F. Yuanzhi, S. Wang, Electrochimica Acta
2020, 353, 136791.

[2] R. Roshandel, F. Ahmadi, Renewable Energy
2013, 50, 921-931.

[3] K.-H. Kim, H.-J. Kim, K.-Y. Lee, J.H. Jang, S.-Y. Lee, E. Cho, I.H. Oh, T.H. Lim, International Journal of Hydrogen Energy
2008, 33, 2783-2789.

[4] M. Mandal, M. Moore, M. Secanell, ACS Applied Materials & Interfaces
2020, 13, 49549-49562.

Figure 1
Advanced Decal Transfer in PEFC Electrode: Effect of Rheology Catalyst Inks and Decal Substrate Property
Authors: Choi Hyunguk , Choi Won young , Choi Seo Won , Lee MyeongHwa , Park Young Je , Lee Nam Jin , Myung Kwang Shik , Jung Yong Min , Ryu Sung Kwan , Yoon Young Gi , Yi Sung Chul , Jung Chiyoung
Published: November 2022

To address the global climate change issues, polymer electrolyte fuel cells (PEFCs) are receiving attention as electrochemical energy conversion devices employing green hydrogen. Notably, the PEFC fuel cell is because the electrochemical reaction occurs on the Catalyst Layer (CL), the CL is the core of the Membrane Electrode Assembly (MEA). The conventional CL is usually prepared from catalyst ink comprising the various catalyst, ionomer, and solvents and deposited via blade coating to the decal substrate. Therefore, it is necessary to confirm the optimal decal transfer conditions based on analyzing the characteristics of the catalyst ink and the decal substrate. In the study, the characterize the internal microstructure of the catalyst ink was confirmed through rheology, and the coating velocity was tunable based on catalyst property. In addition, the characteristics of the various decal substrate were confirmed through Atomic Force Microscopy (AFM) and Contact Angle, and differences including variations in loading amount were confirmed despite the same slurry. The structure of CL on the decal sheet was confirmed through a scanning electron microscope (SEM) surface image and cross-section image, and the distribution of Pt and ionomer was confirmed through Energy Dispersive X-Ray Spectrometer (EDS) mapping. The definition of electrochemical performance between catalyst ink characterizes and decal substrates property was investigated through polarization curves and electrochemical impedance spectroscopy (EIS). Also, cyclic voltammetry (CV) techniques are used to characterize electrochemical surface areas (ECSA) areas of the CL. As a result, the property between the catalyst ink and the decal substrate, based on the difference that occurs in the rheology characterized in the catalyst ink, leads to a variation in the CL structure. Therefore, it is very important to determine the decal process conditions by understanding the characteristics of various catalyst ink on rheology and decal sheet.
Understanding Gas Permeation during High Pressure Operation of PEM Water Electrolyzers
Authors: Khedekar Kaustubh , Van Pelt Christopher Evan , Gebhardt Ryan , Zenyuk Iryna V. , Bender Guido , Mukundan Rangachary , Park Andrew M , Borup Rod L. , Komini Babu Siddharth
Published: November 2022

Governments and industries across the world have initiated implementation of clean hydrogen (H2) to achieve zero emissions, yet significant challenges remain for large scale adoption. With the decreasing renewable electricity cost PEM water electrolyzers (PEMWEs) show significant potential for at scale deployment due to their high faradaic efficiency and high operating current density. To reduce the per kilogram price of hydrogen and increase the overall energy efficiency, PEMWEs need to be operated at high differential pressures (30 to 50 bar) to eliminate the need for compression during storage and transportation1. To achieve high faradaic efficiency, thinner membranes are required to reduce voltage losses within the cell. However, thinner membranes exhibit a higher gas permeation rate which leads to increased crossover of hydrogen from the cathode through the membrane to the anode. Such increased crossover of H2 not only reduces the efficiency but can also result in flammable gas mixtures (lower flammability limit for H2 in O2 is 4 %) as Iridium/Iridium oxide (anode catalyst) is inefficient in oxidizing H2
1. The addition of a gas recombination catalyst (GRC) to the membrane is an useful strategy to oxidize permeating H2 and minimize the H2:O2 ratio at the anode.

In this study, a high pressure (up to 30 bar) electrolyzer setup is coupled with online gas chromatography-mass spectrometry to understand the H2 gas permeation in membranes as a function of H2 partial pressure and operating current density (simulated by varying the flow rates) as shown in Figure 1
. Effect of the GRC, its loading, and its location on the H2 permeation will be elucidated. Differences induced by the addition of anode and cathode catalyst layers on H2 permeation rates will also be presented.

Figure 1. Ex-situ H2 permeation rate at different cathode operating pressure at 80 °C. The anode was maintained at 1 bar of O2 partial pressure

Acknowledgement

This research is supported by the U.S. Department of Energy (DOE) through the Hydrogen and Fuel Cell Technologies Office, program manager Dave Peterson

Reference

Bernt, M., Schröter, J., Möckl, M. & Gasteiger, H. A. Analysis of Gas Permeation Phenomena in a PEM Water Electrolyzer Operated at High Pressure and High Current Density. J. Electrochem. Soc.
167, 124502 (2020).

Figure 1
(Invited) Progress and Perspective Towards Low-Cost High-Performance Anion Exchange Membrane Water Electrolysis
Authors: Strasser Derek James , Pupucevski Max , Macauley Natalia , Lattimer Judith , Zhong Sichen , Xu Hui
Published: November 2022

Hydrogen is at the forefront of clean energy use and storage in the goal to drastically reduce anthropogenic carbon dioxide and combat global climate change. However, hydrogen production to-date is accomplished via steam methane reforming which, for every ton of hydrogen produced 5.5 tons of CO2 is liberated. One viable technical solution for production of clean hydrogen is water electrolysis. To this end DOE has implemented the Hydrogen Earthshot initiative to cleanly produce hydrogen at 2 $/kg by 2025 and 1 $/kg by 2030.

Of the several commercial water electrolysis technologies available, proton exchange membrane water electrolysis (PEMWE) currently offers the most benefits including operations at low temperature, differential pressure, and high current density (≥3 A/cm2). Commercialization of PEMWE has advanced rapidly despite several significant disadvantages which include the necessity of scarce expensive platinum-group metal (PGM) catalysts, expensive perfluorinated membranes, and significant environmental impacts of perfluorinated alkyl substances (PFAS) used in membrane production. The solution to these challenges is the development of alkaline exchange membrane water electrolysis (AEMWE) which retains the advantageous characteristics of PEMWE without the need for PGM catalysts or perfluorinated membranes.

Here in, we report on our current progress of AEMWEs, which covers PGM-free catalyst development, low-cost and durable AEM development and electrode design development. From a commercial point of view, given a high-performance durable membrane, manufacturing MEAs is a critical next step toward commercialization. Therefore, development of an AEM with accessible thermal transitions prior to the onset of quaternary ammonium degradation is key to enabling proven MEA fabrication techniques such as hot-pressing and decal transfer of electrodes. Through a novel synthetic approach, we will describe the preparation of functionalized copolymers and terpolymers containing latent cross-linking functionality. Ultimately, we will demonstrate the manufacturability of MEAs from our PGM-free catalysts and membrane materials employing hot-pressing and decal transfer of electrodes along with single cell evaluations. We will also discuss factors that affect the degradation of AEMWEs and solutions to address these challenges.
(Digital Presentation) Interfacial Durability of Anion Exchange Membrane Water Electrolyzers (AEMWEs)
Authors: Maxwell Derrick , Kendrick Ian , Mukerjee Sanjeev
Published: November 2022

There is a growing industrial appeal of anion exchange membrane water electrolyzers (AEMWEs) to produce hydrogen. This is spurred by the recent advancements in high current density operation capability with relatively low overvoltage performance. Cost reduction has been pursued by reducing the reliance on expensive platinum group metal (PGM) catalysts while still achieving long-term, continuous operation conditions most relevant to the industry: high current densities above 2 A/cm2 while retaining overvoltage performance so that overall cell potential is less than 2V.

Along with a selection of appropriate PGM-free catalysts, other approaches exist that drive down the associated cost to produce hydrogen from water splitting. Sources of water are extended to brackish and even seawater to further drive down costs due to the removal of costly water purification requirements. The introduction of salt to the water source may improve overvoltage performance in an AEMWE by raising electrolyte conductivity, however, it may also lead to some unknown instability within more severe high current operating conditions. The challenge remains that AEMWE durability testing is not standardized, and more minute interfacial degradation mechanisms between ionomer, catalyst, membrane, and electrolyte are not well characterized for many industrially relevant materials. When approaching AEMWE performance improvements with PGM-free and variable electrolyte content in water solution sources, the long-term performance needs to be demonstrated in a stable and reliable manner.

A series of in-situ Raman experiments are presented in coordination with ex-situ spectroscopic and physical analysis of components in PGM-free AEMWEs that are expected to contribute to overall degradation of electrolyzer performance. Interfacial durability improvements are sought by providing insight into the main sources of failure during high current and long-term operations. Electrochemical testing protocols are also developed and presented in order to seek standardization of testing procedures. In-line gas chromatography (GC) analysis is also presented in tandem with other analytical methods to confirm product gas purity and corroborate hypotheses on possible degradation mechanisms.
In-Plane Printed Batteries Based on Mxenes
Authors: Nurpeissova Arailym , Tleukenov Yer-Targyn , Kalimuldina Gulnur , Bakenov Zhumabay
Published: November 2022

In the era of miniaturization, micro energy storage devices become an essential part of the progress in many fields starting from simple sensors to medical devices. However upcoming developments in all these fields are restricted to finding safe, reliable and high-performance micro batteries with the shapes that is not limited only to rectangles, cylinders, and pouches. The research is confronted with challenges of fitting a battery into a microdevice. Lithium-ion batteries (LIBs), a mature energy storage technology, are a leading candidate for the development of micro batteries that can be easily integrated into microelectronic devices. However, despite significant achievements in the field of micro batteries, limitations in areal capacity and in power densities still motivate the search for alternative designs and novel concepts in the battery field. Insufficient areal energy density from planar micro batteries has inspired a search for three-dimensional micro batteries. The power output of a three-dimensional micro battery is expected to be higher than that of a two-dimensional battery of equal size, as a result of the higher ratio of electrode-surface-area to volume and lower Ohmic losses. Within a battery electrode, the 3D architecture provides large surface area, increasing power by reducing the diffusion path for Li ions. Additive manufacturing, also known as 3D printing, has appeared as a novel class of free form fabrication technologies that have a variety of possibilities for the rapid creation of complex architectures at lower cost than conventional methods. 3D printing enables the controlled creation of functional materials with three-dimensional architectures, representing a promising approach for the fabrication of next-generation electrochemical energy-storage devices and has many unique advantages over conventional manufacturing methods. In this work, printer is employed to print a 3D micro battery with MXene electrodes that can be printed easily and can be fitted into any small device.
A New Li–S Battery with an Active Material-Containing Separator Electrically Isolated from Cathode
Authors: Shim Jae Rin , Kim Hye Ran , Ryoo San Deul , Jung Yongju
Published: November 2022

A dramatic increase in the cost of raw materials such as Ni, Co, and Li has caused the battery community to shift its attention to lithium-sulfur (Li-S) cells due to its low cost followed by abundance of S. Despite recent remarkable advances, a series of issues remain unanswered, including poor cycle stability and safety concerns. Above all, the practically attainable energy densities of present Li-S batteries are still much lower than the theoretically achievable limit. Diverse approaches have been explored to tackle these problems. In particular, significant efforts have been made to synthesize porous carbons with sophisticated architectures. It was recently revealed that (1) the enhanced performance of C-S composites are closely associated with the effective confinement of highly soluble polysulfides inside the porous carbon framework, and (2) the insulating nature of elemental sulfur does not affect the electrochemical behavior of sulfur. Indeed, electrically isolated sulfur particles are converted to polysulfides via the reduction of sulfur molecules dissolved in the electrolyte solution. Based on this finding, in this work, we present a new concept of Li-S cells that integrates a sulfur-layered separator along with a pure carbon cathode.
Electrochemical Characteristics of Composite Solid Polymer Electrolytes Containing 1-Dimensional Active Ceramic Filler for All-Solid-State Lithium-Ion Batteries
Authors: Lee Gwi-Hak , Nguyen An-Giang , Kim Jong-Min , Park Chan-Jin
Published: November 2022

Recently, the battery market for electric vehicle (EV) and energy storage system (ESS) is expanding. In addition, attempts and studies to implement a high energy density by applying a lithium metal anode to a Li-ion battery (LIB) system are in progress. However, the conventional organic liquid electrolytes have safety problems, such as a short circuit due to lithium dendrite growth, and a risk of ignition and explosion due to electrolyte leakage. To address the issues, all-solid-state batteries (ASSBs) using stable solid electrolytes have attracted much attention as new-generation batteries. Among solid electrolytes, composite solid polymer electrolyte (CSPE) has excellent merits over existing liquid electrolytes such as no electrolyte leakage, non-flammability, and a wide electrochemical potential window. In addition, various types of inorganic fillers may be introduced to improve electrochemical properties of CSPEs. In this study, the CSPEs were fabricated by incorporating 1D or OD Li0.33La0.557Ti0.99Al0.01O3 (A-LLTO) perovskite solid electrolyte fillers in a PVDF-HFP polymer matrix and their electrochemical properties were investigated. The optimized 1D A-LLTO containing CSPE (1D A-LLTO CSPE) exhibited a high ionic conductivity of 0.21 mS cm-1, a good potential stability of up to 4.87 V for Li/Li+, and a lithium ion transport number of 0.499 at 50 °C. In addition, 1D A-LLTO CSPE showed better thermal stability and electrochemical properties compared with 0D A-LLTO CSPE. The 1D A-LLTO CSPE exhibited a reduced overpotential of about 45 mV for 1000 h in contact with lithium metal at 50 °C. Furthermore, the Li/1D A-LLTO CSPE/NCM622 full cell exhibited satisfactory rate capability, cycling stability with a discharge capacity of 159.95 mAh g-1 and a coulombic efficiency of 97.6% over 100 cycles at a rate of 0.2 C, and performed stable long-term cycling performance at the rate of 0.5 C over 400 cycles at 50 ℃. These results demonstrate that the 1D A-LLTO CSPE is expected to become one of the hopeful candidates for ASSBs.
Polymer Binder with Improved Interfacial Property in the Composite Cathode for All-Solid-State Lithium Batteries
Authors: Lee Young-Jun , Hong Seung-Bo , Sim Hui-Tae , Kim Dong-Won
Published: November 2022

Lithium secondary batteries are used in diverse fields, such as mobile electronics, electric vehicles and energy storage system. As the market for large-scale energy storage gradually increases, high energy density lithium batteries with enhanced safety are required. Among various types of battery systems, all-solid-state lithium batteries (ASSLBs) employing sulfide electrolytes are attracted a great deal of attention due to their enhanced safety and high energy density. When assembling ASSLBs, the composite cathode is usually consisted of active material, sulfide electrolyte, conducting carbon and polymer binder. During charge and discharge processes of ASSLBs, the active materials suffer volume expansion and contraction, resulting in formation of large cracks and void space in the electrode. In this study, we investigate polymer binders with good adhesive and interfacial property for achieving good electrochemical performance of the composite cathode. The effect of type of polymer binder on the cycling performance of ASSLBs will be presented and discussed.
(Digital Presentation) Electrode and Electrolyte Materials for Thin Film Microbatteries
Authors: O'Donoghue Aaron , Mc Grath Louise , Povey Ian , Rohan James F. , Shine Michael
Published: November 2022

Electrode and Electrolyte Materials for Thin Film Microbatteries,

Aaron O’Donoghue, Louise McGrath, Ian Povey and James Rohan

In this work we assess the electrochemical performance of electrodeposited, binder-free V2O5 thin films with Li metal anodes in liquid and polymer gel electrolytes based on a pyrrolidinium based ionic liquid (C4mpyrTFSI). Coulombic efficiencies >99%, with electrode capacities >120 mAh g-1 are obtained in cyclic voltammetry analysis of crystalline V2O5 with C4mpyr-based Ionic liquid (IL) electrolytes. A polymer gel electrolyte suited to layer by layer microbattery fabrication was synthesised and tested with the crystalline V2O5 and gave large electrode capacities at a relatively high rate (110 mAh g-1 at 2 C) similar to those obtained in liquid electrolytes. Stable long-term cycling (up to 400 cycles) is obtained with Li metal anodes without capacity fade or short circuits developing in either the VC containing IL or the polymer gel analogue. In addition, no V2O5 deterioration is observed with the polymer gel electrolyte as the capacity recovered to ~125 mAh g-1 after cycling at 5 C.

Furthermore, we assess surface modification of V2O5 by depositing 3nm Al2O3 via ALD which has been shown to improve the charge-discharge kinetics of oxide electrode materials. Coulombic efficiencies >99%, with peak electrode capacities >120 mAh g-1 are obtained and long-term cycling stabilities up to 625 cycles.

1) L. M. McGrath and J. F. Rohan, Batteries & Supercaps, 4 (2021) 485 – 492, High rate lithium ion cycling in electrodeposited binder-free thin film vanadium oxide cathodes with lithium metal anodes in ionic liquid and polymer gel analogue electrolytes.

2) L. M. McGrath and J. F. Rohan, Molecules, (2020), 25. 6002, Pyrrolidinium containing ionic liquid electrolytes for Li-based batteries.

3) T. Teranishi, Y. Yoshikawa, M. Yoneda, A. Kishimoto, J. Halpin, S. O’Brien, M. Modreanu and I. M. Povey, (2018), ACS Applied Energy Materials, 1(7), pp. 3277-3282, Aluminum Interdiffusion into LiCoO2 Using Atomic Layer Deposition for High Rate Lithium Ion Batteries.

Figure 1: Charge/Discharge capacity of 3nm Al2O3 coated V2O5 vs Li foil in 1M LiPF6 in EC:DEC (1:1)

Figure 1
(Invited) Mg2+ Intercalation into Transition Metal Oxides: What Do We Know and What Would We like to Know?
Authors: Cabana Jordi
Published: November 2022

Li-ion batteries hold the commanding heights of energy storage today. In a quest to further boost energy density, interest exists in batteries that couple a Mg metal anode and an oxide cathode that can intercalate Mg2+ ions. Any technological hope hinges on developing robust experimental verification of intercalation in the oxide is indispensable because competing reactions that are not productive for storage often interfere. Such goal requires a combination of tools providing information at different scales, with synchrotron featuring prominently. In this talk, I will discuss the most up-to-date insight into the ability of oxides to reversibly intercalate Mg2+ in non-aqueous electrolytes, since the use of Mg metal requires rigorously anhydrous environments. We will not only discuss the evidence supporting intercalation of Mg2+, but also delineate emerging correlations with both the identity of the transition metal and the existence of defects in the oxide structure. Critical to the endeavor is the characterization of chemical and physical phenomena using a combination of tools providing information at different scales. The discussion will naturally lead us to reveal foundational bottlenecks and immediate questions that must be addressed to make Mg electrochemistry viable for energy storage.
Expanding the Materials Search Space for Multivalent Cathodes
Authors: Rutt Ann , Persson Kristin A.
Published: November 2022

Multivalent batteries are an energy storage technology with the potential to surpass lithium-ion batteries, however their performance has been limited by the low voltages and poor solid-state ionic mobility of available cathodes. A computational screening approach to identify high-performance multivalent intercalation cathodes among materials that do not contain the working ion of interest has been developed which greatly expands the search space that can be considered for materials discovery. This approach has been applied to magnesium cathodes as a proof of concept and resulting candidate materials are discussed in further detail. In examining the ion migration environment and associated Mg2+ migration energy in these materials, local energy maxima are found to correspond with pathway positions where Mg2+ passes through a plane of anion atoms. While previous works have established the influence of local coordination on multivalent ion mobility, these results suggest that considering both the type of local bonding environment as well as available free volume for the mobile ion along its migration pathway can be significant for improving solid-state mobility.
Lithium Substitution in P3-Structured Copper-Based Cathodes for Sodium-Ion Batteries
Authors: Ronne Arthur , Liu Jue , Yang Xiao-Qing , Chen-Wiegart Yu-chen Karen , Hu Enyuan
Published: November 2022

Sodium-ion batteries promise low-cost energy storage for the grid and electric vehicles, building upon the established “rocking-chair” Li-ion design, while benefitting from the natural abundance of sodium and the ability to utilize iron or copper redox reactions to further reduce the material cost. Nonetheless, Na-ion adoption has been hindered due to low energy density and large structural changes leading to poor long-term cyclability. It has been recently shown that additional reversible capacity can be obtained through oxygen redox with low voltage hysteresis in selected Na-ion layered oxide cathodes. However, the mechanisms and the intermediate species that enable this reversible oxygen redox are highly debated and not fully understood. Here we focus on several P3-structured sodium-deficient NaxY1/3Mn2/3O2 cathodes, where Y can be Cu or derivatives with partial lithium substitution, to elucidate how lithium substitution influences both the redox mechanism and the structural evolution during electrochemical cycling. Our results show a small amount (~7%) of lithium substitution can change the reaction pathway from a two-phase reaction to a solid solution mechanism, increasing stability and capacity retention. A multimodal characterization approach combining synchrotron-based X-ray spectroscopy, microscopy, and scattering techniques along with nuclear magnetic resonance spectroscopy, provides insights into the redox mechanisms, chemical species distribution, structural evolution, and phase transitions during electrochemical cycling.

Acknowledgment: The work at Brookhaven National Laboratory was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Vehicle Technology Office of the U.S. Department of Energy through the Advanced Battery Materials Research (BMR) Program under contract DE-SC0012704. This research used resources of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.
Driving Force behind the Amorphization in the Crystalline Cathode Structures during Alkali Metal Ion Intercalation for Electrochemical Energy Storage
Authors: Ozdogru Bertan , Capraz Omer Ozgur Özgür
Published: November 2022

Development of cathode structures suitable for Na-ion and K-ion batteries is still one of the major challenges on the way to the design of next-generation alkali metal-ion batteries. Although Li, Na and K belong to the same alkali metal group with a single charge in their cation form, intercalation of Na+ and K+ ions in electrodes is difficult since ionic radii of Na+ (0.98 Å) and K+ (1.38 Å) are larger than that of Li+ (0.69Å). Intercalation of alkali metal ions results in volumetric expansions in the electrode structure. Even modest expansions in brittle cathodes can cause particle fracturing in a larger crystalline-size scale. Intercalation of larger ions can cause structural collapse and amorphization induced by continuous accumulation of strains and distortions. However, the lack of understanding behind the amorphization mechanisms in the crystalline electrodes upon ion intercalation materials hinders the development of electrode structures suitable for these large ions.

In the first part of the talk, we will first report the utilization of in situ digital image correlation and in-operando X-ray diffraction (XRD) techniques to probe dynamic changes in the amorphous phase of iron phosphate during potassium intercalation1. A new experimental approach allows to monitor dynamic physical and structural changes in the amorphous phase of the electrodes. This method offers new insights to study mechanics of ion intercalation in the amorphous nanostructures.

In the second part of the talk, we will discuss the electrochemical and mechanical response of the iron phosphate cathodes upon Li, Na and K ion intercalation. Strain evolution during Li and Na intercalation results in more linear dependence on the state of charge / discharge. However, strains generated in the electrode shows nonlinear behavior during insertion / extraction of K ions. Strain rate calculations showed that K ion intercalation results in a progressive increase in the strain rate, whereas Li and Na intercalation induce nearly constant strain rates2. Our results shows that strain rates are critical factor for the amorphization of the crystalline structure, rather than the absolute value of electrochemical strains. These observations provide a fundamental insight into the impact of alkali ions on the redox chemistry and associated chemomechanical deformations.

Acknowledgement: This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (Award number DE-SC0021251).

References:

1) B. Ozdogru et al, Nano Letters, 21, 18, 7579–7586, 2021.

2) B. Ozdogru et. al, Electrochemical Science Advances, e2100106, 2021.
(Invited, Digital Presentation) Design of New Cathodes for Sodium-Ion Batteries Harnessing Anionic Redox Activity: Two Case Studies
Authors: Vanam Sai Pranav , Barpanda Prabeer
Published: November 2022

Sodium-ion batteries (SIBs) are widely pursued as pragmatic alternative to the Li-ion battery technology having close operational similarity along with natural resource abundance. In this sector, apart from classical cationic redox-based cathodes, various new cathodes have been unveiled based on anionic (oxygen) redox activity. In this work, we will showcase two such case studies of novel cathode composition for SIBs exploiting anionic redox activity.

(1) P2-type manganese-rich layered oxides offers high capacity along with fast rate kinetics. To improve their electrochemical properties, reduce voltage decay upon cycling and to mitigate irreversible phase transitions, cation doping or hybrid composite integrations can be explored. We have tested a unique Mn-rich layer-spinel composite, Na0.7(Li1/18Mn11/18Ni3/18Fe2/181
/18)O2–xNa2MoO4, leading to a synergistic effect of layered P2 and spinel phases. This layer/spinel biphasic composite was stabilised through Mo doping and its electrochemical activity was studied at different voltage windows. Upon cycling between 1.5–4.5 V, this Mo-based composite exhibited a high specific capacity of 183 mAh.g-1 involving both cationic and anionic (O2-/O2
n-) redox activity. The structural evolution during (dis)charge was studied by ex-situ X-ray diffraction and cyclic voltammetry. It is observed that mitigating P2-P2´´ phase transition at higher voltage is crucial to improve the electrochemical performance, cycling stability and reduce the voltage hysteresis. The structural and electrochemical properties of this new composite cathode will be described (Fig. a) (manuscript submitted).

(2) The second part will dwell on anionic redox activity of Na-based mixed-metal oxide cathode [Na0.7Mn0.6Ni0.3Co0.1O2]. Combining cationic and anionic redox activity, it exhibited a reversible capacity of 120 mAh/g with anionic redox activity centered around 4.3 V (Fig. b). The underlying redox mechanism has been investigated using in-situ XRD and Raman spectroscopy showing peroxo bond formation (Fig. c). The structural and electrochemical properties of this new cathode composition will be explained (manuscript submitted).

Figure 1
How Does Mg Transport in MgCr2O4 - a Cathode Active Material?
Authors: Mistry Aashutosh , Johnson Ian D. , Ingram Brian J. , Srinivasan Venkat
Published: November 2022

Conventionally, we expect the transport of intercalated species in battery active particles is limited by diffusion. MgCr2O4 has been identified as a candidate active material for the Mg batteries based on its theoretical Mg-storing capacity, high open circuit potential, and acceptable diffusion barrier for Mg-ion transport (1,2). However, when operated electrochemically, its performance does not match the promised potential (3). Motivated by these observations, we examine charge transport in dense MgCr2O4 pellets in an electrolyte-free setup to conclusively probe bulk Mg transport. We find that the ion transport in this material cannot be explained by using the conventional understanding. We propose a new theory that extends the conventional picture and accounts for the unusual behavior in MgCr2O4
(4). We further discuss the implications of this understanding for engineering active material particles in MgCr2O4 porous electrodes.

References

Canepa, P.; Sai Gautam, G.; Hannah, D. C.; Malik, R.; Liu, M.; Gallagher, K. G.; Persson, K. A.; Ceder, G. (2017) "Odyssey of Multivalent Cathode Materials: Open Questions and Future Challenges." Chem. Rev., 117 (5), 4287–4341. DOI: 10.1021/acs.chemrev.6b00614.

Bayliss, R. D.; Key, B.; Sai Gautam, G.; Canepa, P.; Kwon, B. J.; Lapidus, S. H.; Dogan, F.; Adil, A. A.; Lipton, A. S.; Baker, P. J.; Ceder, G.; Vaughey, J. T.; Cabana, J. (2020) "Probing Mg Migration in Spinel Oxides." Chem. Mater., 32 (2), 663–670. DOI: 10.1021/acs.chemmater.9b02450.

Hu, L.; Johnson, I. D.; Kim, S.; Nolis, G. M.; Freeland, J. W.; Yoo, H. D.; Fister, T. T.; McCafferty, L.; Ashton, T. E.; Darr, J. A.; Cabana, J. (2019) "Tailoring the Electrochemical Activity of Magnesium Chromium Oxide towards Mg Batteries through Control of Size and Crystal Structure." Nanoscale, 11 (2), 639–646. DOI: 10.1039/C8NR08347A.

Johnson, I.D.; Mistry, A.; Yin, L.; Murphy, M.; Wolfman, M.; Fister, T. T.; Lapidus, S. H.; Cabana, J.; Srinivasan, V.; Ingram, B. J. (2022) "Investigating Charge Transport in MgCr2O4 Extends the Understanding of Battery Intercalation Hosts.", under review
(Invited) The Complex Mechanisms That Create High Li-Ion Mobility in Oxides and Sulfides
Authors: Ceder Gerbrand
Published: November 2022

The exciting development of solids with extremely high Li-ion conductivity, higher than that in traditional liquid electrolytes, in the last decade has forced us to rethink the processes that make cations move in solids. Super-ionic Li conductors typically have very high Li concentration so that their conductivity behavior cannot be explained with simple point defect mechanisms. Instead, ideas of concerted motion or highly correlated motion have been proposed.

I will discuss our current understanding of the mechanisms that provide high Li-ion conductivity. We find that due to the high screening power of S2- Li mobility in sulfides is mostly determined by local anion coordination and its variation along the migration pathway, making anion topology the main determinant of Li-ion conductivity. As a result, we find that there is little coordinated or concerted motion in sulfides. In contrast, due to the lower screening power of oxides and their lower Li-Li distances, Li-ion conductivity is much more determined by the electrostatic interaction with the other cations, setting the stage for possible concerted motion of multiple ions. I will show how this leads to very specific, but precise rules for selecting structures that may accommodate very fast Li-ion motion.

While fast motion of divalent cations is much less likely, I will show computational results that indicate that even super-ionic motion of ions such as Mg2+ and Ca2+ may be possible in the right framework.
Dual Ion Conducting Solid Electrolyte and Electrochemical Protocol for Interface Design
Authors: Amin Ruhul , Dixit Marm , Parejiya Anand , Essehli Rachid , Muralidharan Nitin , Belharouak Ilias
Published: November 2022

The major challenges for the development of all solid-state batteries (ASSBs), that would be cheaper and can be charged and discharged faster, are stable solid electrolytes and robust interfacial design. We report the dual ion conduction capability of Na-based NASICON type super ion conductor materials using Na1+xMnx/2Zr2-x/2(PO4)3 (NMZP) as a candidate system [1]. This method enables the use of Na-based NASICON material family in both Na as well as Li all solid-state batteries (Figure 1a). The ionic conductivity NZMPs increased as the x value increased and x = 2 showed the highest room temperature conductivities. Crystallographic analysis using neutron diffraction revealed that conductivities observed in these materials are related to the variations in the Na-O bond length and the concentration of mobile sodium content. Using Galvano static plating and stripping tests, we show that these NMZPs boast good cycling stability against both Na and Li metals which also reveals dual ion conduction. Mechanistic investigations through postmortem SEM/EDS and XPS characterizations of the alkali metal and the cycled NMZPs confirm that the Na-Li ion exchange occurs readily in these materials when electrochemically cycled. ASSBs have several interfaces and the interface properties vary depending on the contact condition, energy states, type defects, and chemical/electrochemical stability. ASSB life and performance rely largely on these interfaces since dendrite formation, Li-depleted space-charge layer generation, and spatial variation in interfacial adhesion originate at the interfaces, which leads to battery failure. Stabilizing Li | SE interface is crucial for the development of high-energy-density solid-state batteries. Current approaches in Li metal stabilization employ energy and cost-intensive protocols that have a detrimental impact on the techno-economic feasibility of the ASSBs. This presentation will focus on the facile, electrochemical protocol for improving the interfacial impedance and contact at the Li | Li6.25Al0.25La3Zr2O12 (LALZO) interface. Implementation of a fraction of second short duration high voltage pulse to a poorly formed interface leads to a sustained improvement in contact impedance and lower overpotentials for electrodeposition and electro-dissolution [2] (Figure 1b). This high pulse protocol does not induce the formation of dendrites on the symmetric cells. This electrochemical protocol has direct application in battery formation cycles as well as online management systems for ASSBs.

Reference

[1]. A. Parejiya, R. Essehli, R. Amin, J. Liu, N. Muralidharan, H. M. Meyer, III, D. L. Wood, III, and I. Belharouak, ACS Energy Letters 6 (2021) 429.

[2]. A. Parejiya, R. Amin, M.B. Dixit, R. Essehli, C. Jafta, D.L. Wood, and I. Belharouak., ACS Energy Lett.
6 (2021) 3669.

Figure 1
(Invited) Interfacial Dynamics of Anode-Free Solid-State Batteries
Authors: Dasgupta Neil P.
Published: November 2022

There is significant interest in solid-state batteries (SSBs) as an alternative to traditional Li-ion batteries, as they can potentially eliminate the flammable liquid electrolyte and enable Li-metal anodes. However, manufacturing of SSBs with Li metal anodes poses a significant challenge, owing to the highly reactive nature of Li metal. Therefore, there has been a recent increase in interest in “anode-free” configurations, where the Li metal anode is formed in situ using the pre-existing inventory in the cathode. In addition to manufacturing considerations, anode-free configurations also enhance energy density compared to batteries with excess Li metal in the anode. However, compared to pre-formed Li metal/solid electrolyte interfaces, the nucleation, growth, and stripping of Li metal in anode-free SSBs has not been widely studied, and poses unique electro-chemo-mechanical phenomena.

To probe the dynamic interfacial evolution of anode-free SSBs, in this study, I will present results using a complimentary set of in situ/operando methodologies. First, I will describe the morphological evolution of Li nucleation and growth at garnet LLZO solid electrolytes, using a newly developed platform for operando 3-D video microscopy [1]. In particular, the influence of mechanical stresses on both the thermodynamic and kinetic properties of Li will be discussed, and unique electrochemical signatures of anode-free plating will described. A mechanistic framework for these electro-chemo-mechanics will be presented, which results in design rules for improving the homogeneity of Li plating during anode formation.

To compliment this morphological information, I will also present results using operando x-ray photoelectron spectroscopy (XPS) on sulfide solid electrolytes. This allows for direct observation of SEI formation during in situ anode formation. In particular, we observe a transition in reaction pathways from SEI formation to nucleation of Li metal, which is a function of both the charging protocol and the presence of interlayer coatings [2-3]. Finally, these results will be compared and contrasted to anode-free Li plating in liquid electrolytes, and a discussion will be presented on how to optimize plating morphology and reversibility.

[1] E. Kazyak, M. Wang, K. Lee, S. Yadavalli, A. J. Sanchez, M. D. Thouless, J. Sakamoto, N. P. Dasgupta, Submitted (2022).

[2] A. L. Davis, R. Garcia-Mendez, K. N. Wood, E. Kazyak, K.-H. Chen, G. Teeter, J. Sakamoto, N. P. Dasgupta,
J. Mater. Chem. A
8, 6291 (2020).

[3] A. L. Davis, E. Kazyak, D. W. Liao, K. N. Wood, N. P. Dasgupta, J. Electrochem. Soc.
168, 070557 (2021).
Rapid Screening of Novel Electrolytes for High Calendar Lifetime Lithium-Ion Cells with Silicon-Based Anodes
Authors: Verma Ankit , Colclasure Andrew M. , Turczynski Andrew , Trask Stephen E. , Pupek Krzysztof , Abraham Daniel P.
Published: November 2022

While cycle-life parity between graphite and silicon (Si) based lithium-ion batteries (LIBs) is being reached, calendar lifetime of Si anodes remains disappointing compared to its graphite counterpart1. Silicon anode, owing to its intrinsic high (electro)chemical reactivity, exhibits poorly passivating solid electrolyte interphase (SEI) characteristics in common electrolyte formulations optimized for graphitic systems like LiPF6 salt in EC:EMC solvents. Rapid electrolyte screening for calendar lifetime optimization is essential for enabling silicon anodes, as standardized calendar lifetime estimation with the USABC open circuit voltage reference performance test (OCV-RPT) requires long-duration experiments (~years) for accuracy2. In this work, we perform calendar lifetime screening of novel electrolytes for Si anodes utilizing voltage-hold (V-hold) experiments. The V-hold protocol with shortened runtime (~weeks) affords faster testing as compared to the conventional OCV-RPT protocol. Composite silicon anodes with low (15 wt.% Si) and high contents of silicon (70 wt. %Si) are tested with fluorine-free electrolyte systems (e.g. LiBOB in EC:EMC) and EC free electrolytes (e.g. LiPF6 in FEC:EMC) respectively. Capacity during the V-hold has reversible anode lithiation and irreversible SEI growth contributions; consequently, a physics-based capacity deconvolution algorithm is devised to accurately split the parasitic currents for quantitative calendar lifetime estimation. The development of this synergistic experiment-modeling testing paradigm aids in the identification of electrolyte compositions that form stable, passivating SEI films on the silicon-based anodes.

Figure 1 shows the voltage-hold cycle data for (a) fluorine-free and (b) fluorine-rich (right) electrolytes with 15% Si composite anodes collected in a 3-electrode cell. The corresponding normalized capacity and current profiles for 4.1V hold portion are shown in (c) and (d) respectively. Accurate deconvolution of irreversible capacity from the hold capacity is needed to obtain SEI stability information for calendar lifetime.

1McBrayer, J.D., Rodrigues, M.T.F., Schulze, M.C., Abraham, D.P., Apblett, C.A., Bloom, I., Carroll, G.M., Colclasure, A.M., Fang, C., Harrison, K.L. and Liu, G., 2021. Calendar aging of silicon-containing batteries. Nature Energy, 6(9), pp.866-872.

2U.S. Department of Energy Vehicle Technologies Program, United States Advanced Battery Consortium Battery Test Manual For Electric Vehicles, Revision 3.1, October 2020 http://www.uscar.org/guest/article_view.php?articles_id=86

Figure 1
Reduced Electrolyte Reactivity of Pitch-Carbon Coated Si Nanoparticles for Li-Ion Battery Anodes
Authors: Schulze Maxwell C , Fink Kae , Palmer Jack , Carroll Mike Michael , Dutta Nikita , Zweifel Christof , Engtrakul Chaiwat , Han Sang-Don , Neale Nathan R. , Tremolet de Villers Bertrand J.
Published: November 2022

Silicon-based anodes for Li-ion batteries (LIB) have the potential to increase the energy density over graphite-based LIB anodes. However, silicon anodes exhibit poor cycle and calendar lifetimes due to mechanical instabilities and high chemical reactivity with the carbonate-based electrolytes that are typically used in LIBs. In this work, we synthesize a pitch-carbon coated silicon nanoparticle composite active material for LIB anodes that exhibits reduced chemical reactivity with the carbonate electrolyte compared to an uncoated silicon anode. Silicon primary particle sizes <10 nm minimize micro-scale mechanical degradation of the anode composite, while conformal coatings of pitch-carbon minimized the parasitic reactions between the silicon and the electrolyte. When matched with a high voltage NMC811 cathode, the pitch-carbon coated Si anode retains ~75% of its initial capacity over 1000 cycles. Efforts to increase the areal loading of the pitch-carbon coated silicon anodes to realize real energy density improvements over graphite anodes results in severe mechanical degradation on the electrode level. Developing procedures to engineer the architecture of the composite silicon anode may be a solution to this mechanical challenge.

Figure 1