Intercalation Batteries Research Articles

(Industrial Electrochemistry and Electrochemical Engineering Division H. H. Dow Memorial Student Achievement Award) Tailoring Electrode-Electrolyte Interfaces through Non-Covalent Interactions for Electrochemical Energy Storage and Conversion

Li-ion batteries and fuel cells play essential roles in electrifying transportation. Central to the electrochemical systems is the electrode-electrolyte interface, where (electro)chemical surface reactions or intercalation occur, and its thermodynamic and kinetic properties determine the energy density, power density, and lifetime of the electrochemical devices. However, the molecular structures at the electrical double layer and reaction mechanisms remain poorly understood, hindering the rational material design for more efficient electrochemical devices. This talk focuses on the mechanisms of (electro)chemical reactions and charges transfer kinetics at the electrode-electrolyte interface, providing design principles based on non-covalent interactions in electrolytes.First, an in situ Fourier-transform infrared spectroscopy (FTIR) method was developed for Li-ion batteries, which revealed unique evidence for dehydrogenation of carbonate electrolytes on Ni-rich lithium nickel, manganese and cobalt oxides (NMC), accounting for interface impedance build-up and battery capacity fading. Based on the proposed mechanism, strategies on suppressing electrode and electrolyte reactivity were demonstrated to improve battery cycling. Next, the kinetic mechanism for ion intercalation at the electrode-electrolyte interface will be discussed. Li-ion concentration-dependent intercalation kinetics was demonstrated from charge-adjusted electrochemical experiments and fit into a coupled ion-electron transfer mechanism, which governed the current-dependent maximum capacity and power density of intercalation batteries. Finally, for electrocatalytic reactions central to fuel cell technologies, we demonstrated tuning interfacial hydrogen bonding through protic ionic liquids with different acid dissociation constants and organic solvents with different donor numbers to tailor oxygen-reduction reaction (ORR) and hydrogen evolution reaction (HER). Strengthening hydrogen bonding between ORR products and ionic liquids, or between interfacial water molecules facilitated proton-coupled electron transfer kinetics, revealed by in situ surface-enhanced infrared absorption spectroscopy and density functional theory (DFT) calculations. The study can pave the way for the electrolyte and electrode design of electrochemical storage devices with improved energy and power density and cycle life.

Inherent Behavior of Electrode Materials of Lithium-Ion Batteries.

For independency from the fossil fuels and to save environment, we need to move toward the green energies, which requires better energy storage devices, especially for usage in electric vehicles. Li-ion and beyond-lithium insertion batteries are promising to this aim. However, they suffer from some inherent limitations which must be understood to allow their development and pave the way to find suitable energy storage alternatives. It is found that each positive or negative electrode material (cathode or anode) of the intercalation batteries has its own behavioral (charge-discharge) properties. The modification of preparation parameters (composition, loading density, porosity, particle size, etc.) may improve some aspects of the electrode performance, but cannot change the intrinsic property of the electrode itself. Accordingly, these properties are called as the "inherent behavior characteristics" of the active material. It is concluded that the behavior of a specific electrode substance, even following different preparation routes, depends only on diffusion mechanisms. This work shows that the inherent electrode properties can be visualized by representation of current density vs. capacity.

Navigating phase diagram complexity to guide robotic inorganic materials synthesis

Efficient synthesis recipes are needed to streamline the manufacturing of complex materials and to accelerate the realization of theoretically predicted materials. Often, the solid-state synthesis of multicomponent oxides is impeded by undesired by-product phases, which can kinetically trap reactions in an incomplete non-equilibrium state. Here we report a thermodynamic strategy to navigate high-dimensional phase diagrams in search of precursors that circumvent low-energy, competing by-products, while maximizing the reaction energy to drive fast phase transformation kinetics. Using a robotic inorganic materials synthesis laboratory, we perform a large-scale experimental validation of our precursor selection principles. For a set of 35 target quaternary oxides, with chemistries representative of intercalation battery cathodes and solid-state electrolytes, our robot performs 224 reactions spanning 27 elements with 28 unique precursors, operated by 1 human experimentalist. Our predicted precursors frequently yield target materials with higher phase purity than traditional precursors. Robotic laboratories offer an exciting platform for data-driven experimental synthesis science, from which we can develop fundamental insights to guide both human and robotic chemists.

Evaluation of MXene Ti3C2 Charge–Discharge Behaviors as an Electrode Material for Intercalation Batteries

Eliminating A element from the MAX phases, the resulted 2D structure, named MXene, can be used as the electrode material for the intercalation, namely, Li‐ion, Na‐ion, K‐ion, and Mg‐ion batteries. MXene Ti3C2, produced by etching Ti3AlC2, is a promising intercalation electrode material, which is systematically evaluated in this article by taking data from literature. The diagrams provide a manner to assess and compare the most important characterizations, i.e., rate‐capability and performance. The evaluations show that the synthesis methods of the pristine MAX phase as well as the final MXene play vital roles on the properties. The rank of synthesis methods and also commercial pristine material is recognized and reported based on the analyzed properties. Moreover, effectiveness of the additives, dopants, compositing, nanosizing, and etching is assessed precisely. Also, comparison between different types of intercalation batteries regarding the usage of MXene as the electrode is performed. This article paves the way for future studies and evaluations of this kind of electrode materials. It guides the researchers to modify, design, and engineer their manufactured electrodes to meet higher quality of the properties.

Evaluation of Ti3C2 as electrode material for Li, Na, Mg, Al, K, Ca, and Zn -ion intercalation batteries: A DFT study

Layered structures attracts attention as the intercalation host structures. MAX-phases are a family of ternary layered carbides and nitrides, with general formula Mn+1AXn. By etching the A parameter out of MAX-phase layers, MXene uses as electrode material in different intercalation batteries. In the present work, we use noble approaches for density functional theory (DFT) calculations to evaluate Ti3C2 MXene as an intercalation electrode for Li-ion, Na-ion, Mg-ion, Al-ion, K-ion, Ca-ion, and Zn-ion batteries. The evaluated electrode materials are Ti3LiC2, Ti3NaC2, Ti3MgC2, Ti3AlC2, Ti3KC2, Ti3CaC2, and Ti3ZnC2, respectively. The structural, electrical, electrochemical, and bonding properties of the Ti3C2-MXene with and without the intercalating ion are studied. Two deintercalated structures are investigated, called 1st and 2nd deintercalated structures. Consequently, we conclude that Ti3C2 MXene is a superior electrode material for the intercalation batteries at least regarding to its structural (2nd deint. st.) and electrical properties. However, Ca, K, and Na -ion cells may have a problem for their 1st (de)intercalation cycle. This study helps future investigations for MXene electrode materials. Also, it provides an appropriate methodology to study analogous materials.

Electroactive Prussian Blue Analogues/TiO2 Nanocomposites Obtained through SILAR Assembly in Mesoporous Nanoarchitectures

AbstractThe preparation of nanomaterials for energy applications such as intercalation batteries and materials that can act as substrates for water oxidation is a subject of major interest nowadays. In this work, we report the deposition of Prussian blue (PB) and its cobalt analogue (CoPBA) on mesoporous titania thin films (MTTF) using the successive ionic layer adsorption reaction (SILAR) technique under soft conditions. A bifunctional ligand, 1,10‐phenanthroline‐5,6‐dione (pd), was used to functionalize the titania surface and promote the growth of PB and CoPBA. The resulting PB@MTTF and CoPBA@MTTF nanocomposites were characterized using several techniques and it was determined that PB and CoPBA grow in a controlled and sequential manner, maintaining the mesoporous architecture. Both PB@MTTF and CoPBA@MTTF demonstrated very good electroactive properties, while CoPBA@MTTF exhibited water oxidation capabilities. The flexibility of this PBA@MTTF platform allows the incorporation of any labile transition metal ion or fragment into the structure of the coordination polymer embedded into a mesoporous matrix, opening the door for (photo)electrochemical devices and catalysts.

(Energy Technology Division Graduate Student Award sponsored by BioLogic) Probing and Engineering Electrode-Electrolyte Interfaces in Electrochemical Energy Storage and Conversion

Climate change demands the development of clean energy technologies, where rechargeable batteries and fuel cells promise a bright future by integrating with solar or wind energy. Li-ion batteries and fuel cells also play essential roles in electrifying transportation in replacement of internal combustion engines. Central to these electrochemical systems is the electrode-electrolyte interface, where (electro)chemical surface reactions or intercalation reactions occur, and its thermodynamic and kinetic properties determine the energy density, power density, and lifetime of the electrochemical devices. However, the molecular structures at the interface and how they promote or suppress the desired reactions remain unclear, hindering the rational design of electrode-electrolyte interfaces to improve the performance of electrochemical devices.This talk focuses on the fundamental understanding of the interfacial (electro)chemical reaction mechanisms at the molecular level and charges transfer kinetics at the electrified interfaces. First, an in situ Fourier-transform infrared spectroscopy (FTIR) method was developed to examine the parasitic reactions between carbonate electrolytes and lithium nickel, manganese and cobalt oxides (NMC) in Li-ion batteries, and unique evidence for dehydrogenation reactions on Ni-rich NMC was revealed, which accounted for interface impedance build-up and battery capacity fading. Based on the proposed mechanism, strategies based on electrolyte non-covalent interactions were demonstrated to improve battery lifetime. In the second part of the talk, the research extended in situ FTIR characterization and electrolyte engineering to electrocatalytic reactions central to fuel cell technologies. An interfacial layer of protic ionic liquids with different acid dissociation constants were found to enhance the oxygen-reduction reaction (ORR), attributed to strengthened hydrogen bonding between ORR products and ionic liquids, revealed by in situ surface-enhanced infrared absorption spectroscopy and density functional theory (DFT) calculations. For the hydrogen evolution reaction (HER), similarly, promoting hydrogen bonding between interfacial water molecules also facilitated proton-coupled electron transfer kinetics, resulting in favorable HER in controllable organic confinements. Finally, this talk will introduce fundamental, theoretical aspects of charge transfer processes at the electrode-electrolyte interface - the kinetic mechanism for ion intercalation. Experimental evidence from a charge-adjusted electrochemical method showed that Li-ion intercalation occurs by coupled ion-electron transfer (CIET), which governs the current-dependent maximum capacity and power density of intercalation batteries. these research efforts have laid a solid foundation for the rational design of electrochemical interfaces employing the physical chemistry of electrodes and electrolytes, for next-generation electrochemical storage devices with improved energy and power density and cycle life.

Extended Conjugation Acceptors Increase Specific Energy Densities in π-Conjugated Redox Polymers

Organic materials are a sustainable alternative to replace inorganic transition metal-based cathodes in rechargeable intercalation batteries. Among the possible redox active organic materials, conjugated polymers with multiple redox sites per repeat unit are expected to afford high energy and power densities while being resistant to dissolution when in contact with battery electrolytes. However, accessing the full capacity of polymeric electrodes while ensuring electrochemical reversibility has been challenging. Using diketopyrrolopyrrole (DPP)-based donor–acceptor (D–A) polymers as model systems and complementary electrochemical experiments and first-principles calculations, we show that conjugated backbone moieties that minimize charge localization on the electron accepting repeat units lead to near theoretical discharge capacities. Further, the capacity enhancement is associated with better rate performance and improved electrochemical stability of the polymer over prolonged cycling. Our work suggests that charge density on the electron accepting moiety is a potential descriptor for rationally designing redox-active polymer electrodes that afford high discharge capacities along with a long cycle life.

Chemistry-mechanics-geometry coupling in positive electrode materials: a scale-bridging perspective for mitigating degradation in lithium-ion batteries through materials design.

Despite their rapid emergence as the dominant paradigm for electrochemical energy storage, the full promise of lithium-ion batteries is yet to be fully realized, partly because of challenges in adequately resolving common degradation mechanisms. Positive electrodes of Li-ion batteries store ions in interstitial sites based on redox reactions throughout their interior volume. However, variations in the local concentration of inserted Li-ions and inhomogeneous intercalation-induced structural transformations beget substantial stress. Such stress can accumulate and ultimately engender substantial delamination and transgranular/intergranular fracture in typically brittle oxide materials upon continuous electrochemical cycling. This perspective highlights the coupling between electrochemistry, mechanics, and geometry spanning key electrochemical processes: surface reaction, solid-state diffusion, and phase nucleation/transformation in intercalating positive electrodes. In particular, we highlight recent findings on tunable material design parameters that can be used to modulate the kinetics and thermodynamics of intercalation phenomena, spanning the range from atomistic and crystallographic materials design principles (based on alloying, polymorphism, and pre-intercalation) to emergent mesoscale structuring of electrode architectures (through control of crystallite dimensions and geometry, curvature, and external strain). This framework enables intercalation chemistry design principles to be mapped to degradation phenomena based on consideration of mechanics coupling across decades of length scales. Scale-bridging characterization and modeling, along with materials design, holds promise for deciphering mechanistic understanding, modulating multiphysics couplings, and devising actionable strategies to substantially modify intercalation phase diagrams in a manner that unlocks greater useable capacity and enables alleviation of chemo-mechanical degradation mechanisms.

Chemical Preintercalation Synthesis of Versatile Electrode Materials for Electrochemical Energy Storage.

ConspectusThe widespread use of electrical plants and grids to generate, transmit, and deliver power to consumers makes electricity the most convenient form of energy to transport, control, and use. Balancing electricity demand with electricity supply requires a mechanism for energy storage, which is enabled by electrical energy storage devices such as batteries and supercapacitors. In addition to the grid-level energy storage, we have all witnessed the quick growth of a number of applications that require autonomous power, illustrated by the Internet of Things, and electrification of transport. Batteries, when developed for targeted applications with specific requirements, require new materials with improved performance enabled by rational design on the atomic level. The material tunability knobs include chemical composition, structure, morphology, and heterointerfaces, among others. Synthesis methods that could enable control of these parameters while offering versatility and being facile are highly desired.In this Account, we describe a synthesis strategy for the creation of new intercalation host oxides, hybrid materials, and compounds with oxide/carbon heterointerfaces for use as electrodes in intercalation batteries. We begin by introducing a strategy called the chemical preintercalation synthesis approach and describing processing steps that can be used to tune the material's chemical composition, structure, and morphology. We then show how the chemical preintercalation of inorganic ions can be used to improve the ion diffusion and stability of the synthesized materials. We reveal how confined interlayer water can be controlled and how the degree of hydration affects the electrochemical performance. This is followed by a demonstration of the chemical preintercalation of organic molecules leading to unprecedented expansion of the interlayer region up to ∼30 Å and initial electrochemical characterization of the obtained hybrid materials. We then present evidence that the carbonization of the interlayer organic molecules is an efficient synthetic pathway for creating oxide/carbon heterointerfaces and improving the electronic conductivity of oxides, which leads to improved stability and rate capability during electrochemical cycling. The examples discussed in this Account show that the chemical preintercalation synthesis approach opens pathways for the preparation of materials that have not been synthesized previously, such as new phases, hybrid materials, and 2D heterostructures with advanced functionalities. We demonstrate that chemical preintercalation can be used to effectively tune the chemistry of the confined interlayer region in layered phases and form tight oxide/carbon heterointerfaces enabling control of the material properties at the atomic level.

A modelling framework for efficient reduced order simulations of parametrised lithium-ion battery cells

AbstractIn this contribution, we present a modelling and simulation framework for parametrised lithium-ion battery cells. We first derive a continuum model for a rather general intercalation battery cell on the basis of non-equilibrium thermodynamics. In order to efficiently evaluate the resulting parameterised non-linear system of partial differential equations, the reduced basis method is employed. The reduced basis method is a model order reduction technique on the basis of an incremental hierarchical approximate proper orthogonal decomposition approach and empirical operator interpolation. The modelling framework is particularly well suited to investigate and quantify degradation effects of battery cells. Several numerical experiments are given to demonstrate the scope and efficiency of the modelling framework.

A systematic evaluation of charge-discharge behaviors, performance, and rate-capability of Al-ion batteries

The improvement of the intercalation electrodes for Al-ion batteries needs a deep understanding of the relation of charge-discharge parameters, especially the specific capacity (C) and the charge-discharge rate (R). In this paper, we extract many experimental charge-discharge data (C and R) from the literature. Evaluating the data, we employ an approach which has been proposed for the normalization and standardization of the intercalation batteries’ data. The approach presents an appropriate manner for assessing the goodness of a given electrode and cell performance. The data of Al-ion batteries’ electrode materials show more distribution in comparison with Li-ion and Na-ion batteries. We find that the distribution of the curves is due to three main parameters, namely synthesis method, electrolyte type, and substrate of the electrode. It is found that among the considered materials the carbon-based electrodes including graphene, carbon nanotube, and graphite provide the best performance and rate-capability, while the MoS2 electrode shows the poorest one. It is concluded that (de)intercalation of AlCl4− ions has a faster kinetic than Al3+ ions. Accordingly, an insight for the perspective of the future researches of the intercalation batteries is suggested. This study helps finding appropriate materials (electrode, electrolyte, and substrate), and paves the way for optimization of the cells. Noteworthy, this paper is vanguard for this kind of evaluations and its methodology can be used for other kind of cells and electrodes.

Towards Efficient Thermal Management within Intercalation Batteries through Electrolyte Convection

Ubiquitous in consumer electronics and emergent in transportation and stationary applications, lithium-ion batteries (LIB) are the state-of-the-art energy storage technology due to their energy density, roundtrip efficiency, and cycle life.1,2 While the past decade has seen a steady decline in battery price and concomitant increase in energy density due to a combination of materials development, manufacturing advances, and market scale,3,4 current LIBs are still unable to meet the often incongruous power and energy requirements of newer applications (e.g., fast charging of energy-dense batteries).5,6 In addition, these more extreme operating environments challenge battery longevity and safety, necessitating responsive balance-of-plant systems which include thermal management systems that control cell temperatures using heat transfer media. At elevated temperatures, accelerated solid-electrolyte interphase growth and component decomposition may lead to capacity/power fade,7,8 and, in the worst cases, thermal runaway and hazardous releases. Within the battery cell, temperature gradients lead to non-uniform electrode reaction distribution, and subsequently reduced cell performance and cycle life.8 Thus, typical LIB operating temperature ranges are constrained between 20 ℃ and 40 ℃, with minimal temperature differences across the cell. Most current thermal management systems rely on heat exchange through the surface or tab of the cell with a cooling media (air, liquid, phase-change materials, etc.).9,10 While generally sufficient under many of today’s applications (low C-rates), this approach can be challenged by newer applications, such as those that require high power input/output (EV fast charging, electric aviation), or need large battery formats (stationary storage systems).In this presentation, we will describe a novel concept of thermal management through forced convection of the electrolyte through the porous electrodes and separator. By leveraging battery simulation and dimensional analysis, we demonstrate that: (1) electrolyte convection provides efficient heat removal capability by carrying the generated heat out of the cell through the flowing medium; (2) the elimination of electrolyte concentration gradient by flow, and the resulting smaller ohmic resistance, concentration and activation overpotentials, help prevent cell temperature rise through reduced heat generation rate. Compared to current thermal management systems, this approach offers several important potential advantages, including (1) reduced internal temperature gradient, (2) rapid response time to temperature regulation, (3) simplifications to manufacturing, and ultimately, and (4) reduced system costs and improved battery safety.

Memory Effects' Mechanism in the Intercalation Batteries: The Particles' Bipolarization.

To develop energy-storage devices, understanding their charge-discharge behaviors and their underlying mechanisms is mandatory. Memory effect (ME) is among the most important behaviors that should be understood, influencing the batteries' applications. In this paper, the intercalation batteries' ME and their features are justified and explained by employing the particles' bipolarization mechanism. Diffuse regions, located in both sides of the reactant/product phases, turn the particles into dipoles (bipolarized particles) during/after the processes. This bipolarization and subsequent neutralization can explain many charge-discharge behaviors, including the ME. Here, the mechanism explains and justifies all the known features and some aspects of the phenomena which have not been considered so far. According to the proposed mechanism, the aged-neutralized particles react later and in a higher voltage than the fresh-neutralized particles, causing a bump in the curve called the ME. It is the same mechanism that causes the increase in the charge voltage by increasing the open-circuit voltage rest time. Our experiments sufficiently verified the mechanism. In the paper, impacts of the average particle size, relaxation/rest time, discharge cutoff voltage of the memory-writing cycle (MWC), Li-mobility kinetics, current rate, state of charge, depth of discharge of the MWC, boundaries of the charge-discharge curve, and so forth are considered, and their influences on the ME are explained. This mechanism sheds light on the relevant characteristics of the batteries and helps design, tune, control, and engineer the behaviors.

A polymeric cathode-electrolyte interface enhances the performance of MoS2-graphite potassium dual-ion intercalation battery

Anion intercalation in the graphite cathode of a dual-ion battery (DIB) occurs at unusually high voltage (>4.5 V K + /K). This exacerbates electrolyte degradation and corrosion of Al current collectors, leading to poor coulombic efficiency (CE), typically <90%, and short cell life as a result. These limitations can be mitigated if a stable cathode-electrolyte interface layer (CEI) can form on the graphite electrode. In this study, we demonstrate that the performance of a potassium-based DIB can be improved with a triallyl phosphate (TAP) monomer added in 6 m KN(SO 2 CF 3 ) 2 (KTFSI)-dimethyl carbonate (DMC) electrolyte. The TAP additive forms a stable polymeric CEI on the graphite particles and thus increases the CE of the cell to 97%–99%. Together with MoS 2 -negative electrodes with a pre-formed solid electrolyte interphase (SEI) layer, the DIB concept has been shown to offer specific capacities from ∼40 to 80 mAh g −1 with an average discharge voltage of 3.7 V. • Design principle for high-performance MoS 2 -graphite dual-ion battery is proposed • Impact of electrolyte additives on the negative and positive electrodes is investigated • Triallyl phosphate is used to generate a polymeric CEI on graphite cathode • MoS 2 with pre-formed SEI layer ensures stable cycling and high coulombic efficiency A dual-ion battery operates at unusually high voltage, which is needed to intercalate anions in a graphite cathode. Asfaw et al. explore strategies to create more stable electrode-electrolyte interfaces in an effort to design potassium-based MoS 2 -natural-graphite dual-ion battery with high coulombic efficiency and long cycle life.

Direct Lithium Recovery from Aqueous Electrolytes with Electrochemical Ion Pumping and Lithium Intercalation.

In this mini-review, we provide an account of recent developments on electrochemical methods for the direct extraction of lithium (DEL) from natural brines, geothermal fluids, seawater, and battery recycling electrolytes by ion-pumping entropy cells. A critical discussion of selected examples with the LiMn2O4 lithium intercalation battery cathode material is presented, with emphasis on the operation parameters, some experimental results and multiscale simulations, some limitations and challenges, and conditions for industrial scaleup.

Magnetoelectric coupling lights up spintronics path: Lithium battery ideas to tune magnetism

Magnetoelectric coupling lights up spintronics path: Lithium battery ideas to tune magnetism

Nimh Gas Model for Dynamic Behaviour Study

The NiMH battery is an intercalation battery with a positive NiOH electrode and a negative metal hydride electrode. The electrolyte used is a highly alkaline aqueous solution, typically 6:1 KOH:LiOH. As a consequence of this and the reaction potentials of the electrodes, splitting of water into its constituting elements is a part of normal battery operation. When charging at high SOC, as well as when overcharging, oxygen is formed as a side-reaction. It then diffuses through the separator and recombines at the negative electrode. This recombination cycle causes the temperature in the battery to rise, something that is commonly used to terminate battery charging, either through ΔT or -ΔV criteria. In addition to oxygen production at high state of charge, overdischarging of the battery can produce hydrogen at the positive electrode, with a pressure increase at end of discharge indicating a harmful overdischarge of the battery [1]. Hydrogen is also present in the battery gas composition as a consequence of the negative hydrogen intercalation electrode material which is in equilibrium with gaseous hydrogen, an equilibrium which shifts with electrode hydrogen content [2]. Figure Left: A schematic showing the main gas reactions in the metal NiMH battery. Right: An example cycle of a NiMH battery, showing cell voltage (blue), cell gas pressure (green) and cell surface temperature (teal).The internal gas reactions of the NiMH battery have a great impact on battery function, both in regard to energy efficiency and battery aging. While measurements of battery internal total gas pressure occur in some battery systems, measurements of individual constituents would be impractical in the field, as such measurements require laboratory equipment. Therefore, a gas model that can estimate the internal pressure distribution under dynamic conditions would be a valuable tool to study the effects of different application drive cycles, as well as a possibility to further enhance BMS function for battery stability and longevity.There have been many attempts at modeling the gaseous side reactions in the NiMH battery. Some of these models are part of comprehensive battery models, which combines a voltage response model with added side reactions [3,4]. Other models look only at specific gas related processes [5]. However, a limitation with these models is that they are not able to model the battery during dynamic current conditions. The main reason for this is the presence of a strong open circuit voltage hysteresis, something that these models do not capture well.This study presents a model of the gas reactions and heat generation in the NiMH battery. The model is not coupled to a voltage model, instead it simulates internal temperature and pressure when supplied with experimental current, voltage and surface temperature data. This removes the complication of the open circuit voltage hysteresis effect and lets us model dynamic battery behavior. The model is in zero dimensions and based on physical principles. There are several parameters that are optimized by fitting to experimental data. The model is then validated by simulating pressure for a second set of data, based on the fitted values of the parameters. The simplicity of the model not only allows for it to be used in battery monitoring hardware, it can also be coupled to voltage and multidimensional models to build a more comprehensive predictive model.References Notten, P. H. L.; Latroche, M. Nickel-Metal Hydride: Metal Hydrides. In Encyclopedia of Electrochemical Power Sources; Garche, J., Dyer, C., Moseley, P., Ogumi, Z., Rand, D., Scrosati, B., Eds.; Elsevier B.V., 2009; Vol. 50, pp 502–521.Tserolas, V.; Katagiri, M.; Onodera, H.; Ogawa, H. Thermodynamical Modeling of P-C Isotherms for Metal Hydride Materials. Trans. Mater. Res. Soc. Japan 2010, 35 (2), 221–226. https://doi.org/10.14723/tmrsj.35.221.Albertus, P.; Christensen, J.; Newman, J. Modeling Side Reactions and Nonisothermal Effects in Nickel Metal-Hydride Batteries. J. Electrochem. Soc. 2008, 155 (1), A48. https://doi.org/10.1149/1.2801381.Ledovskikh, A.; Verbitskiy, E.; Ayeb, A.; Notten, P. H. L. Modelling of Rechargeable NiMH Batteries. J. Alloys Compd. 2003, 356–357, 742–745. https://doi.org/10.1016/S0925-8388(03)00082-3.Notten, P. H. L.; Ouwerkerk, M.; Ledovskikh, A.; Senoh, H.; Iwakura, C. Hydride-Forming Electrode Materials Seen from a Kinetic Perspective. J. Alloys Compd. 2003, 356–357, 759–763. https://doi.org/10.1016/S0925-8388(03)00085-9. Figure 1

Modeling Current Density Non-Uniformity to Detect Premature Failure in 3D Lithium-Ion Batteries

Conventional Lithium-ion (Li-ion) intercalation batteries that are composed of planar cathode, separator, and anode layers bear an intrinsic trade-off between energy density and power density. While thick electrodes allow for more active material loading and higher energy densities, thick electrodes lengthen ion transport pathways and limit power and fast charging performance. Conversely, thin electrodes have fast ion transport at the cost of reduced material loading which leads to lower energy densities. Due to the high weight and volume ratio of inactive components, stacking layers of thin planar batteries is inefficient for high capacity cells.1 Three-dimensional (3D) batteries decouple the power-energy trade-off in planar batteries by modifying electrode architecture on a micron to millimeter scale.2 3D batteries redistribute electrode material beyond planar geometry to controlled 3D spatial arrangements in pursuance of shorter ion-transport pathways and enhanced fast charging behavior in a battery cell. This enables high power performance without sacrificing the mass of active material in the cell, and ideally maintains high energy and power performance at high discharge and charge rates. However, a known issue in 3D batteries is the inhomogeneous transport distances between electrodes leading to nonuniform current density and local depletion of the electrode or electrolyte material.3,4 These nonuniformities can terminate a discharge or charge cycle prematurely. Although many 3D batteries have been proposed to date, few comparative modeling studies have been conducted for these architectures to understand their relative performance gains.In this work, we adapt a two-dimensional current density uniformity index (UI) measure from previous work5 and investigate its usage as a potential 3D metric for quantifying premature failure in 3D batteries. A series of 3D batteries are simulated using the software AMPERES that models a 3D electrochemical systems at the continuum level using volume-averaging techniques.6 Two material models – LiFePO4 (LFP) | Li4Ti5O12 (LTO) and LiNi0.5Mn0.3Co0.2O2 (NMC532) | Graphite – are investigated for each 3D battery architecture. We also visualize 3D Li-ion concentration profiles and Li-ion transport pathways to qualitatively analyze the transport behavior in each 3D battery. Our results show that 3D battery performance is material dependent, and 3D batteries with premature depletion demonstrate high UI metrics early in a discharge cycle. References C. L. Cobb and S. E. Solberg, J. Electrochem. Soc., 164, A1339–A1341 (2017).C. L. Cobb and M. Blanco, Journal of Power Sources, 249, 357–366 (2014).R. Hart, H. White, B. Dunn, and D. Rolison, Electrochemistry Communications, 5, 120–123 (2003).A. A. Talin, D. Ruzmetov, A. Kolmakov, K. McKelvey, N. Ware, F. El Gabaly, B. Dunn, and H. S. White, ACS Appl. Mater. Interfaces, 8, 32385–32391 (2016).D. Grazioli, V. Zadin, D. Brandell, and A. Simone, Electrochimica Acta, 296, 1142–1162 (2019).S. Allu, S. Kalnaus, S. Simunovic, J. Nanda, J.A. Turner, and S. Pannala, Journal of Power Sources, 325, 42–50 (2016). Acknowledgements This work was funded in part by a Defense Advanced Research Projects Agency (DARPA) Young Faculty Award under grant number D19AP00038. The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government.

Li-ionic control of magnetism through spin capacitance and conversion

<h2>Summary</h2> Magnetoelectric (ME) coupling has gradually developed into one of the core means of advancing ultralow-power memory, logic, and sensor technologies. Among various strategies, magneto-ionic control of magnetism based on mechanisms such as redox, intercalation/deintercalation, and charge accumulation can be achieved in ion battery or capacitor systems. In this work, we demonstrate an ME effect originating from the spin capacitance, combining the advantages of intercalation batteries and supercapacitors. Giant, fast, and reversible modulations on the saturation magnetization of ferromagnets are achieved by Li ion motion across the ferromagnet/lithionic conductor interfaces at no more than 1 V. Furthermore, the magnetic evolution driven by the conversion reaction between FeO and Fe over a larger voltage range demonstrates ferromagnetic ordering of the FeO surface. These findings not only open new perspectives for developing high-performance magneto-ionic devices but also are crucial to designing spintronic devices composed of iron and oxide multilayer structures.