Simulation Modeling of All-Solid-State Battery

… First, modeling efforts pertaining to Li-metal anodes and dendrite initiation and growth … anodes to next generation all-solid-state anodes. Second, chemo-mechanics modeling of the SSE …

… contact areas were simulated for a film-type Li|LiPON|LiCoO 2 all-solid-state Li-ion battery. The … the multi-length scale contacts in all-solid-state batteries. The contact area and pressure …

All solid-state batteries are promising high-energy-density storage devices. To optimize their performance without costly trial and error approaches, microstructure-resolved continuum models have been proposed to understand the influence of the electrode architecture on their capabilities. We discuss the recent advances in the microstructure-resolved modeling of solid-state batteries. While not all of the experimentally observed phenomena can be accurately represented, these models generally agree that the low ionic conductivity of the solid electrolyte is a limiting factor. We conclude by highlighting the need for microstructure-resolved models of degradation mechanisms, manufacturing effects and artificial intelligence approaches speeding up the optimization of interfaces in all solid-state-battery electrodes

When it comes to energy density, all-solid-state batteries are seen as a promising technology for next-generation electrochemical storage devices. Nevertheless, the performance of all-solid-state c...

… To enhance all-solid-state battery performance, optimization of the electrode structure … accurate simulations is essential. However, conventional pseudo-two-dimensional simulations are …

All-solid-state batteries (ASSBs) present a promising route toward safe and high-power battery systems in order to meet the future demands in the consumer and automotive market. Composite cathodes are one way to boost the energy density of ASSBs compared to thin-film configurations. In this manuscript, we investigate composites consisting of β-Li3PS4 (β-LPS) solid electrolyte and high-energy Li(Ni0.6Mn0.2Co0.2)O2 (NMC622). The fabricated cells show a good cycle life with a satisfactory capacity retention. Still, the cathode utilization is below the values reported in the literature for systems with liquid electrolytes. The common understanding is that interface processes between the active material and solid electrolyte are responsible for the reduced performance. In order to throw some light on this topic, we perform 3D microstructure-resolved simulations on virtual samples obtained via X-ray tomography. Through this approach, we are able to correlate the composite microstructure with electrode performance and impedance. We identify the low electronic conductivity in the fully lithiated NMC622 as material inherent restriction preventing high cathode utilization. Moreover, we find that geometrical properties and morphological changes of the microstructure interact with the internal and external interfaces, significantly affecting the capacity retention at higher currents.

… electrolyte (SE), of an all-solid-state battery (ASSB), is presented. … The new method we developed to simulate the SE-coated … Our simulations suggest that the SE coating promotes more …

… simulated cold press fabrication and intercalation damage in a sulfide All-Solid-State Battery … We developed a new cohesive hybrid-particulate model that both can simulate particle …

… All-solid-state batteries (ASSBs) with solid-state electrolytes and lithium-metal anodes have been regarded as a promising battery … is of great importance to battery development. To …

… First, we consider the simulated discharge over a range of different rates corresponding to the experimental rates. The resulting simulated cell potential vs capacity for the planar and the …

All-Solid-state batteries (ASSBs) are non-flammable and safe and have high capacities. Thus, ASSBs are expected to be commercialized soon for use in electric vehicles. However, because the electrode active material (AM) and solid electrolyte (SE) of ASSBs are both solid particles, the contact between the particles strongly affects the battery characteristics, yet the correlation between the electrode structure and the stress at the contact surface between the solids remains unknown. Therefore, we used the results of numerical simulations as a dataset to build a machine learning model to predict the battery performance of ASSBs. Specifically, the discrete element method (DEM) was used for the numerical simulations. In these simulations, AM and SE particles were used to fill a model of the electrode, and force was applied from one direction. Thus, the stress between the particles was calculated with respect to time. Using the simulations, we obtained a sufficient data set to build a machine learning model to predict the distribution of interparticle stress, which is difficult to measure experimentally. Promisingly, the stress distribution predicted by the constructed machine learning model showed good agreement with the stress distribution calculated by DEM.

The digital twin technique has been broadly utilized to efficiently and effectively predict the performance and problems associated with real objects via a virtual replica. However, the digitalization of twin electrochemical systems has not been achieved thus far, owing to the large amount of required calculations of numerous and complex differential equations in multiple dimensions. Nevertheless, with the help of continuous progress in hardware and software technologies, the fabrication of a digital twin‐driven electrochemical system and its effective utilization have become a possibility. Herein, a digital twin‐driven all‐solid‐state battery with a solid sulfide electrolyte is built based on a voxel‐based microstructure. Its validity is verified using experimental data, such as effective electronic/ionic conductivities and electrochemical performance, for LiNi0.70Co0.15Mn0.15O2 composite electrodes employing Li6PS5Cl. The fundamental performance of the all‐solid‐state battery is scrutinized by analyzing simulated physical and electrochemical behaviors in terms of mass transport and interfacial electrochemical reaction kinetics. The digital twin model herein reveals valuable but experimentally inaccessible time‐ and space‐resolved information including dead particles, specific contact area, and charge distribution in the 3D domain. Thus, this new computational model is bound to rapidly improve the all‐solid‐state battery technology by saving the research resources and providing valuable insights.

All-solid-state batteries (ASSBs) have been considered as the next generation of lithium-ion batteries. Physics-based models have the advantage of providing internal electrochemical information. To promote physics-based models in real-time applications, in this study, a series of model reduction methods are applied to obtain a reduced-order model (ROM) for ASSBs. First, analytical solutions of the partial differential equations (PDEs) are derived by the Laplace transform. Then, the Padé approximation method is used to convert the transcendental transfer functions into lower order fractional transfer functions. Next, the concentration distributions in electrodes and electrolytes are approximated by parabolic and cubic functions, respectively. Due to the fast calculation of concentration distributions in real time, the equilibrium potential, overpotentials, and battery voltage can now be directly calculated. Compared with the original PDE-based model, the voltage errors of the proposed ROM are less than 2.6 mV. Compared with the voltage response of experimental data, a good agreement can be observed for the ROM under three large C-rates discharging conditions. The calculation time of ROM per step is within 0.2 ms, which means that it can be integrated into a battery management system. The proposed ROM achieves excellent performance and a better tradeoff between model fidelity and computational complexity.

A mathematical model of a Li/LiPON (Lithium Phosphorus Oxynitride)/LiCoO 2 all-solid-state thin-film microbattery was developed. It is isothermal, one-dimensional and takes into …

Replacement of Li-ion liquid-state electrolytes by solid-state counterparts in a Li-ion battery (LIB) is a major research objective as well as an urgent priority for the industry, as it enables the use of a Li metal anode and provides new opportunities to realize safe, non-flammable, and temperature-resilient batteries. Among the plethora of solid-state electrolytes (SSEs) investigated, garnet-type Li-ion electrolytes based on cubic Li7La3Zr2O12 (LLZO) are considered the most appealing candidates for the development of future solid-state batteries because of their low electronic conductivity of ca. 10−8 S cm−1 (RT) and a wide electrochemical operation window of 0–6 V vs. Li+/Li. However, high LLZO density (5.1 g cm−3) and its lower level of Li-ion conductivity (up to 1 mS cm−1 at RT) compared to liquid electrolytes (1.28 g cm−3; ca. 10 mS cm−1 at RT) still raise the question as to the feasibility of using solely LLZO as an electrolyte for achieving competitive energy and power densities. In this work, we analyzed the energy densities of Li-garnet all-solid-state batteries based solely on LLZO SSE by modeling their Ragone plots using LiCoO2 as the model cathode material. This assessment allowed us to identify values of the LLZO thickness, cathode areal capacity, and LLZO content in the solid-state cathode required to match the energy density of conventional lithium-ion batteries (ca. 180 Wh kg−1 and 497 Wh L−1) at the power densities of 200 W kg−1 and 600 W L−1, corresponding to ca. 1 h of battery discharge time (1C). We then discuss key challenges in the practical deployment of LLZO SSE in the fabrication of Li-garnet all-solid-state batteries.

… All-solid-state batteries constitute a very promising energy storage device. Two very important properties of these battery … of discrete-element method simulations and the intrinsic …

Electrochemical impedance spectroscopy (EIS) is a powerful technique to study interface kinetics in lithium ion batteries. In order to separate the contributions of the working and …

In the pursuit for future mobility, solid-state batteries open a wide field of promising battery concepts with a variety of advantages, ranging from energy density to power capability. However, trade-offs need to be addressed, especially for large-scale, cost-effective processing, which implies the use of polymeric binder in the composite electrodes. Here, we investigate three-dimensional microstructure models of active material, solid electrolyte and binder to link cathode design and binder content with electrode performance. Focusing on lithium ion transport, we evaluate the effective ionic conductivity and tortuosity in a flux-based simulation. Therein, we address the influence of electrode composition and active material particle size as well as the process-controlled design parameters of void space and binder content. Even though added in small amounts, the latter has a strong negative influence on the ion transport paths and the active surface area. The simulation of ion transport within four-phase composites is supplemented by an estimation of the limiting current densities - illustrating that application-driven cell design starts at the microstructure level.

The goal of the work presented here was to develop a simulation approach for studying the effects of materials and geometry on the performance of Li‐ion Solid State Batteries (SSB). Simulation provides the opportunity to explore, with ease, different material properties and cell geometries to optimize a Li‐ion SSB's performance. Simulations shown in this paper are time‐dependent and consider electrochemical reaction, heat transfer, the diffusion of Li‐ions and electrons in the electrolyte, and solid Li diffusion in the positive electrode. A 2D model was simulated and the results shown. The simulations were able to show discharge curves, heat flux, the concentration of Li‐ions, electrons, and solid Li at any time in the discharge cycle. Copyright © 2015 John Wiley & Sons, Ltd.

… The aim of the current paper is to develop a mathematical model for all-solid-state Li-ion batteries, which includes all important physical and electrochemical characteristics and is …

In recent times, there has been significant enthusiasm for the development of all solid state batteries. This interest stems from a dual focus on safety—addressing concerns related to toxic and flammable organic liquid electrolytes—and the pursuit of high energy density. \cite{SCHNELL2018160,Zheng2018}. While liquid electrolyte batteries constitute for now the vast majority of commercial cells, solid electrolyte batteries show great promise. In parallel with experimental research, computational models \cite{GrazioliEtAlCM2016} clarify the several fundamental physics \cite{LiMonroeARCBM2020} that take place throughout battery operations. We review some classical models, emphasizing the conceptual advancements documented in the most recent works.

… in Solid-State Batteries (SSBs) is one of the main reasons for their low performance. Although modeling … We present here a three-dimensional physics-based modeling workflow to …

… both experimental and computational approaches can be used as inputs for ML screening models. These models might be able to overcome some of the challenges, such as cost, scale …

… This study presents an experimental characterization and electro-thermal model for a next-… , electrical modeling using a third-order equivalent circuit, and thermal modeling with a …

Solid-state batteries use composites of solid ion conductors and active materials as electrode materials. The effective transport of charge carriers and heat thereby strongly determines the overall solid-state battery performance and safety. However, the phase space for optimization of the composition of solid electrolyte, active material, additive is too large to cover experimentally. In this work, a resistor network model is presented that successfully describes the transport phenomena in solid-state battery composites, when benchmarked against experimental data of the electronic, ionic, and thermal conductivity of LiNi0.83Co0.11Mn0.06O2-Li6PS5Cl positive electrode composites. To highlight the broadness of the approach, literature data are examined using the proposed model. As the model is easily accessible and expandable, without the need for high computing power, it offers valuable guidance for experimentalists helping to streamline the tedious process of performing a multitude of experiments to understand and optimize the effective transport of composite electrodes. Effective conductivity is a key performance indicator for solid-state battery electrodes that is influenced by both composition and microstructure. Here, authors present a simple resistor network model to guide the development of composite electrodes towards optimized effective transport.

Solid‐state batteries with lithium‐metal anodes have emerged as a promising alternative to traditional lithium‐ion batteries thanks to their enhanced energy density and safety. However, the integration of solid‐state electrolytes is still hindered by mechanical instabilities caused by the rigid nature of the system. Stress and strain can be transferred at the interface between electrodes and solid electrolyte, inducing material damage during cycling. To address this issue, a comprehensive understanding of the interplay between electrochemical reactions and mechanical effects is crucial. In this article, a critical review of various approaches to model the multiphysics behavior of Li‐metal solid‐state batteries is provided by analyzing their advancements and limitations. The focus lies on workflows which simulate the effect of microstructural and material property changes on the degradation processes. Continuum modeling of three key chemo‐mechanical challenges is explored: dendritic growth from Li‐metal anodes, structural instability in composite cathodes, and solid electrolyte degradation caused by the formation of unstable interphases. The conclusion highlights the existing challenges and upcoming trends in multiphysics and microscale modeling of batteries.

… /electrode interfaces impedes the development of solid-state batteries (SSBs). To mitigate this … A pseudo-3D physics-based model was developed using semi-empirical parameters to …

Solid-state batteries (SSBs) are crucial for next-generation energy storage because of their higher energy density, better safety, and longer cycling stability compared with traditional liquid-electrolyte batteries. However, their real-world application is limited by issues at the interface, such as dendrite formation, mechanical instability, and low ionic conductivity. Modeling and simulation techniques at the atomic and mesoscale levels have become key tools for understanding, predicting, and solving these issues. This review offers an overview of recent theoretical methods related to SSB interfaces, behavior, and performance. This review also covers the structural, kinetic, and electrochemical characteristics of the LiPON solid electrolyte using computational and theoretical approaches. Interfacial interactions, defect formation energetics, and the breakdown products controlling the electrochemical stability of LiPON against lithium (Li) metal are examined in this study. LiPON was selected as a model system due to its proven interfacial and electrochemical stability, high ionic conductivity, and wide utilization in thin-film all-solid-state batteries, providing a reliable platform for understanding interface-controlled processes. We conclude with a discussion of the current challenges, limitations of existing methods, and outline promising pathways for accurately modeling and predicting complex solid-state battery interface phenomena.

… It accurately predicts the variations in battery voltage and … for an all-solid-state battery with dimensions of 80 × 60 mm. The spatiotemporal evolution of stress and strain in both the battery …

… All-solid-state batteries (ASSBs) are emerging as promising energy storage solutions owing … This study employs a multiphysics approach by combining the discrete element method (…

All-solid-state battery (ASB) system has been considered a promising energy storage system to advance the next generation of electronic devices. However, it is known that LiNi0.8Co0.1Mn0.1O2 (NCM811) as electrode provokes...

… (Si)-based all-solid-state batteries (ASSBs) is hindered by … a three-dimensional multiphysics framework to systematically … an in-depth understanding of the multiphysics interplays in the …

… Multiphysics ® 5.3. Computational model, Fig. 1e, was imported in the COMSOL Multiphysics ® … the user-defined functions within the COMSOL Multiphysics ® . In this study, direct solver …

All-solid-state batteries (ASSBs) are high-energy, high-power batteries. To enhance the understanding of the electrochemical-mechanical behavior in ASSBs across different scales, we …

Dendrite growth and crack propagation are two major hurdles on the road towards the large‐scale commercialization of lithium metal all‐solid‐state batteries (ASSBs). Due to the high multiphysics coupled nature of the underlying dendrite growth mechanism, understanding it has been difficult. Herein, for the first time, an electrochemical‐mechanical model is established that directly couples dendrite growth and crack propagation from a physics‐based perspective at the cell level. Results reveal that overpotential‐driven stress propels a crack to penetrate through the solid electrolyte, creating vacancies for dendrite growth, leading to the short circuit of the battery. Thus, high lithiation/charging rate and low conductivity of electrolytes can accelerate the electrochemical failure of the battery. It is further discovered that Young's modulus ELLZO of the electrolyte has competing contributions to the fracture and dendrite growth; specifically, when ELLZO = 40–100 GPa, the short circuit is triggered early. A larger toughness value hinders the crack propagation and mitigates the Li dendrite growth. The developed multiphysics model provides an in‐depth understanding of the coupling of crack propagation and dendrite growth within ASSBs and an insightful mechanistic design guidance map for robust and safe ASSB cells.

All-solid-state lithium-based batteries represent a critical evolution in energy storage, offering enhanced safety, higher energy density, and superior fast-charging capabilities. However, …

All-solid-state batteries (ASSBs) are high-energy and power-dense batteries. To enhance the understanding of electrochemo–mechanical behavior in ASSBs across various scales, we …

… Promoting the continued development of solid-state lithium batteries requires resolving the … with electrochemical-temperature-mechanical multiphysics fields. The maximum height, …

The safety and energy density of solid-state batteries can be, in principle, substantially increased compared with that of conventional lithium-ion batteries. However, the use of solid-state electrolytes instead of liquid electrolytes introduces pronounced complexities to the solid-state system because of the strong coupling between different physicochemical fields. Understanding the evolution of these fields is critical to unlocking the potential of solid-state batteries. This necessitates the development of experimental and theoretical methods to track electrochemical, stress, crack, and thermal fields upon battery cycling. In this Perspective, we survey existing characterization techniques and the current understanding of multiphysics coupling in solid-state batteries. We propose that the development of experimental tools that can map multiple fields concurrently and systematic consideration of material plasticity in theoretical modeling are important for the advancement of this emerging battery technology. This Perspective provides introductory material on solid-state batteries to scientists from a broad physical chemistry community, motivating innovative and interdisciplinary studies in the future.

… All-solid-state batteries (ASSBs) have emerged as a key … This study develops a multiphysics coupling model for Si-… The effects of C-rates and solid electrolyte conductivity on battery …

… In order to verify the accuracy of the proposed SEM and the validity of the SOC estimation based on the SMO, it is evaluated in conjunction with the battery data in COMSOL Multiphysics…

Recent studies presented the advantages of incorporating solid-polymer-electrolyte (SPE) interlayers in all-solid-state batteries (ASSB). Still, drawbacks regarding the cell performance …

… models sprout for different electrode materials and battery types, but are missing for solid electrolyte … electrode/solid electrolyte intermediate layer, and the electrochemical reactions are …

… It was already known that the performance of solid state electrochemical cells such as … solid electrolyte gas electrodes, independent research groups proposed different reaction models …

… electrochemistry of coupled electronic and ionic degrees of freedom. Existing continuum models of the EDL in solid electrolytes … The defect concentrations in solid electrolytes, including …

… the electrochemical reactions at the Li-metal|SEI|electrolyte … to illustrate how predictive modeling was used to address the … insulating but ionic conductive solid electrolyte interface (SEI) …

Nonuniform electrodeposition of lithium during charging processes is the key issue hindering development of rechargeable Li metal batteries. This deposition process is largely controlled by the solid electrolyte interphase (SEI) on the metal surface and the design of artificial SEIs is an essential pathway to regulate electrodeposition of Li. In this work, an electro‐chemo‐mechanical model is built and implemented in a phase‐field modelling to understand the correlation between the physical properties of artificial SEIs and deposition of Li. The results show that improving ionic conductivity of the SEI above a critical level can mitigate stress concentration and preferred deposition of Li. In addition, the mechanical strength of the SEI is found to also mitigate non‐uniform deposition and influence electrochemical kinetics, with a Young's modulus around 4.0 GPa being a threshold value for even deposition of Li. By comparison of the results to experimental results for artificial SEIs it is clear that the most important direction for future work is to improve the ionic conductivity without compromising mechanical strength. In addition, the findings and methodology presented here not only provide detailed guidelines for design of artificial SEI on Li‐metal anodes but also pave the way to explore strategies for regulating deposition of other metal anodes.

… (SE) meet, a phenomenon of high relevance for the solid-state lithium-metal … models can provide. Thus, this paper aims to bring together electrochemistry, fluid dynamics, and solid …

… -solid-state batteries with a Li anode and ceramic electrolyte have the potential to deliver a step change in performance compared with today’s Li-ion batteries … Simulated dendrite length …

Abstract Lithium metal all-solid-state batteries (ASSBs) are promising candidates for future lithium batteries thanks to their high safety performance and energy density. However, Li dendrite growth and interfacial failure are the two fatal issues deteriorating the cyclability that hinders the wide commercialization of ASSBs. To further understand the underlying mechanisms, a coupled electrochemical-mechanical phase-field model for grain crack propagation and lithium dendrite growth is proposed from the energy conservation perspective in this study. We discover that longer defect with sharp edge and angle ( θ ≥ 45 ° ) causes more severe crack propagation and leads to larger dendrite growth area due to the increased strain energy density. We observe that the initial defect within grain plays an irrelevant role in the dendrite growth within the grain boundary. Stacking pressure greater than 10 MPa significantly speeds up crack propagation as well as dendrite growth due to the nontrivial mechanical driving force. Mechanical stress-induced strain-energy would contribute to more than 15% of the total dendrite growth once the stacking pressure exceeds 20 MPa, while it is trivial if the stacking pressure is below 10 MPa. Large enough fracture threshold strain can prevent the crack propagation. Results provide a fundamental tool for the design and evaluation of ASSB safety and cyclability from a more comprehensive perspective and clear the barrier for the development of next-generation ASSBs.

… in solid-state electrolyte (SE). Different from previous work, in which dendrite growth and … filled crack region, in present model, dendrite growth is not synchronized with crack propagation…

… (A) Schematic of loading conditions used in modeling kinked propagation of metal dendrites. The most energetically favorable propagation angle θ as a function of the flaw inclination β …

… dendrites in garnet-based solid-state lithium metal batteries has been extensively studied by researches [48,49,50]. During operation and transportation, lithium batteries are … simulation …

… In solid state lithium batteries, lithium dendrites are prone to nucleate and grow at unstable … structure and reduce battery capacity. Aiming at the problem of lithium dendrite growth in …

… To comprehensively investigate the effect of strain on dendrite growth in all-solid-state batteries with cracks, we simulated dendrite growth under different strains, and the …

… This work thus provides a fundamental understanding of the mechanical inhibition effect on the dendrite growth in solid-state batteries and can potentially guide the selection and …

Solid-state lithium metal batteries using garnet-type Li7La3Zr2O12 electrolytes hold immense promise for next-generation energy storage, but grain boundary defects promote lithium redistribution and dendrite formation, compromising performance and safety. To address this, we investigate lithium behavior at these boundaries using machine learning potentials and molecular dynamics simulations. Energy minimization drives lithium accumulation or depletion at grain boundaries depending on cavity fraction and local lithium concentration. Crack-like boundary voids facilitate lithium protrusions and dendrites at the electrolyte/negative electrode interface, increasing short-circuit risks. Controlled grain boundary melting achieves selective amorphization while preserving bulk crystallinity. This structural modification slightly reduces ionic conductivity but enhances interfacial electronic and mechanical properties, suppressing lithium aggregation and alleviating interfacial protrusions. In this work, we demonstrate how grain boundary structures govern lithium redistribution dynamics and dendrite formation mechanisms. We further propose targeted grain boundary amorphization as an effective strategy to engineer robust solid-state electrolyte microstructures that improve battery cyclability and safety. Solid-state lithium batteries suffer from lithium dendrite formation that compromises safety. Here, authors reveal how grain boundary structures affect lithium behavior and show that selective amorphization can suppress dendrites and enhance battery stability.

… The mechanism of lithium dendrite penetration in solid-state … of SE does not inhibit dendrite penetration. It is because the … ” by the much softer lithium dendrites. Considering MEC, the …

Density Functional Theory (DFT) calculations of electrode material properties in high energy density storage devices like lithium batteries have been standard practice for decades. In contrast, DFT modelling of explicit interfaces in batteries arguably lacks universally adopted methodology and needs further conceptual development. In this paper, we focus on solid-solid interfaces, which are ubiquitous not just in all-solid state batteries; liquid-electrolyte-based batteries often rely on thin, solid passivating films on electrode surfaces to function. We use metal anode calculations to illustrate that explicit interface models are critical for elucidating contact potentials, electric fields at interfaces, and kinetic stability with respect to parasitic reactions. The examples emphasize three key challenges: (1) the "dirty" nature of most battery electrode surfaces; (2) voltage calibration and control; and (3) the fact that interfacial structures are governed by kinetics, not thermodynamics. To meet these challenges, developing new computational techniques and importing insights from other electrochemical disciplines will be beneficial.

… Finally, we show that ab initio molecular dynamics simulations of the NaCoO 2 /Na 3 PS 4 interface model predict that the formation of SO 4 2– -containing compounds and Na 3 P is …

… several aspects involved with the detailed modeling of solid-solid interfaces. A practical scheme was developed to compute an intensive measure of the interface interaction Cγlim …

… of the interfacial reactions and insight for the future design and … at these critical solid/solid interfaces in SSBs for different types … on various models for the interfacial kinetics. Although the …

Summary The influence of interfaces represents a critical factor affecting the use of solid-state batteries (SSBs) in a wide range of practical industrial applications. However, our current understanding of this key issue remains somewhat limited. Therefore, this review presents the mechanisms and advanced characterization techniques associated with interfaces in SSBs. First, we compare liquid- and solid-state batteries and emphasize the challenges in solid-solid interfaces. Second, we discuss different aspects of interfaces including interphase formation, cathode-electrolyte interface, anode-electrolyte interface, and interparticle interface, which contain a detailed description of the formation mechanisms and current research. Third, the characterization strategies for effective interfacial observation and analysis are summarized and discussed. In particular, two unique characterization techniques, vibrational sum-frequency generation spectroscopy and on-chip single-nanowire battery characterization, are highlighted. Lastly, we summarize the scientific issues associated with solid-solid interfaces and provide our perspectives to better understand the fundamental issues and improve the performance of SSBs.

… solid–solid interface. By these means, we find that Sn–Li and Sn–Na anodes enable high-capacity, dendrite-free battery … the equivalent circuit model to decouple the interfacial transport …

Solid-state ionic conductors find application across various domains in materials science, particularly showcasing their significance in energy storage and conversion technologies. To effectively utilize these materials in high-performance electrochemical devices, a comprehensive understanding and precise control of charge carriers’ distribution and ionic mobility at interfaces are paramount. A major challenge lies in unravelling the atomic-level processes governing ion dynamics within intricate solid and interfacial structures, such as grain boundaries and heterophases. From a theoretical viewpoint, in this Perspective article, my focus is to offer an overview of the current comprehension of key aspects related to solid-state ionic interfaces, with a particular emphasis on solid electrolytes for batteries, while providing a personal critical assessment of recent research advancements. I begin by introducing fundamental concepts for understanding solid-state conductors, such as the classical diffusion model and chemical potential. Subsequently, I delve into the modelling of space-charge regions, which are pivotal for understanding the physicochemical origins of charge redistribution at electrified interfaces. Finally, I discuss modern computational methods, such as density functional theory and machine-learned potentials, which offer invaluable tools for gaining insights into the atomic-scale behaviour of solid-state ionic interfaces, including both ionic mobility and interfacial reactivity aspects. This article is part of the theme issue ‘Celebrating the 15th anniversary of the Royal Society Newton International Fellowship’.

… where S A−B is the area of the interface, E i A−B is the energy of the interface model after a full relaxation of the system and N j and μ j are the number of atoms and the chemical …

All-solid-state batteries offer a significant advancement in energy density and safety compared to conventional lithium-ion battery technologies. However, their development is critically impeded by the complex instability of solid-solid interfaces. These buried junctions, governed by intricate chemical, electrochemical, and mechanical degradation processes, present substantial scientific challenges that cannot be effectively addressed by a single research methodology. This review emphasizes the crucial role of a synergistic paradigm that integrates computational simulations with advanced experimental characterization to overcome these significant interface issues. A conceptual framework is proposed that categorizes this synergistic approach into four hierarchical levels: Foundational, which validates essential material properties; Dynamic, which captures real-time interface evolution using operando techniques; Multi-Scale, which links atomic-scale changes to macroscopic failures; and Intelligent, which harnesses artificial intelligence and machine learning to accelerate discovery and enhance data analysis. Through detailed case studies, the vital role of this integated approach is demonstrated in elucidating ionic transport mechanisms, predicting interfacial reaction pathways, deconstructing the multiphysics of lithium-dendrite growth, and understanding chemo-mechanical failures in composite electrodes. It is concluded that this synergistic methodology is essential for transitioning from descriptive analysis to the predictive, rational engineering of stable, high-performance interfaces necessary for the next generation of energy storage systems.

Solid‐state batteries (SSBs) are considered as one of the most promising candidates for the next‐generation energy‐storage technology, because they simultaneously exhibit high safety, high energy density, and wide operating temperature range. The replacement of liquid electrolytes with solid electrolytes produces numerous solid–solid interfaces within the SSBs. A thorough understanding on the roles of these interfaces is indispensable for the rational performance optimization. In this review, the interface issues in the SSBs, including internal buried interfaces within solid electrolytes and composite electrodes, and planar interfaces between electrodes and solid electrolyte separators or current collectors are discussed. The challenges and future directions on the investigation and optimization of these solid–solid interfaces for the production of the SSBs are also assessed.

Enabling long cyclability of high-voltage oxide cathodes is a persistent challenge for all-solid-state batteries, largely due to their poor interfacial stabilities against sulfide solid electrolytes. While protective oxide coating layers such as LiNbO3 (LNO) have been proposed, its precise working mechanisms are still not fully understood. Existing literature attributes reductions in interfacial impedance growth to the coating's ability to prevent interfacial reactions. However, its true nature is more complex, with cathode interfacial reactions and electrolyte electrochemical decomposition occurring simultaneously, making it difficult to decouple each effect. Herein, we utilized various advanced characterization tools and first-principles calculations to probe the interfacial phenomenon between solid electrolyte Li6PS5Cl (LPSCl) and high-voltage cathode LiNi0.85Co0.1Al0.05O2 (NCA). We segregated the effects of spontaneous reaction between LPSCl and NCA at the interface and quantified the intrinsic electrochemical decomposition of LPSCl during cell cycling. Both experimental and computational results demonstrated improved thermodynamic stability between NCA and LPSCl after incorporation of LNO coating. Additionally, we revealed the in-situ passivation effect of LPSCl electrochemical decomposition. When combined, both these phenomena occurring at the first charge cycle result in a stabilized interface enabling long cyclability of all-solid-state batteries.

… We present a new model for all solid-state lithium ion batteries that takes into account … , our model describes transient lithium ion flux through a solid electrolyte, the solid–solid interfaces …

… that quantifying interface contact more accurately reflects the correlation between actual solid-solid … This work provides critical theoretical guidance for optimizing interface design and …

… to deal with solid-solid contact, providing considerable maintenance of interface stability. … cathode materials and broadens the design guidance toward improving interfacial integrity. …

High interfacial resistance between a cathode and solid electrolyte (SE) has been a long-standing problem for all-solid-state batteries (ASSBs). Though thermodynamic approaches suggested possible p...

… However, a continuum model that is based on the … scale of a realistic microstructure of a battery cell, and therefore, a … In this paper, we propose a continuum model that resolves the …

… The design of solid state batteries with lithium anodes is attracting attention for the prospect … be controlled as a factor in solid state battery design. The accessible interface morphologies, …

… new solid state battery designs with comparable performance to current lithium-ion cells. For a high-fidelity model of a solid-state battery… A continuum-level model is said to be physically …

This work presents a thermodynamically consistent model for all-solid-state lithium-ion batteries (ASSBs), formulated within the framework of coupled electro-chemo-mechanics of continua at finite strains. A distinctive feature of the model is the inclusion of a dual conduction mechanism within the solid electrolyte. The formulation is sufficiently general to capture the inelastic response of electrodes, whether metallic (as in viscoplastic lithium foil anodes) or porous. The mechanical behaviour of ASSBs is investigated under galvanostatic discharge conditions, accounting for both the stripping of the lithium foil—here replicated by tailored boundary conditions—and the shrinking of the porous cathode. The governing equations have been implemented in a commercial finite-element code. Numerical simulations reveal the influence of individual components on the overall cell response, identify limiting factors during charge and discharge cycles and support the optimization of cell design.

… Solid-State Diffusion Model To illustrate the working principle of continuum representation and charge/discharge modeling, we start with a simple diffusion model that governs the …

In all‐solid‐state batteries (ASSBs), the mechanical stress generated during electrode (de)lithiation plays a critical role in determining the cell longevity because of the induced degradation mechanisms. This stress originates from local volume fluctuations in the active electrode materials, such as nickel‐rich LiNixMnyCozO2, which are intrinsically coupled to spatial variations in lithium‐ion concentration during electrochemical cycling. Herein, a novel ASSB model that considers electrochemistry and solid mechanics in a one‐way coupled manner is presented. The model spatially resolves 3D‐microstructure of an ASSB half‐cell generated from wet manufacturing process simulations and is based on linear continuum mechanics. The coupling of electrochemistry and solid mechanics is incorporated via lithiation‐dependent volumetric changes of the active material and the microstructural changes due to deformed geometries affecting the particles percolation paths. Furthermore, it is shown that the overall volume change of the half‐cell is dependent on the C‐rate and on the applied stack pressure. Finally, the findings demonstrate that solid‐mechanical effects and their interplay with electrochemical phenomena significantly impact the evolution of interfacial surface area and the total pore volume. These factors are crucial for ensuring accurate computational predictions, underscoring the necessity of incorporating such interactions in battery modeling approaches.

… All-Solid-State Batteries (ASSBs) represent a transformative solution for … continuum model, using methods from prior research [1] , Finite Element Analysis (FEA), to simulate the battery’s …

This study develops a coupled mechanical‐electrochemical multiphase‐field model to describe the evolution of interface voids during the discharge of solid‐state lithium batteries. The model accounts for void collapse induced by the viscoplastic flow of lithium metal under stacking forces and incorporates the microscopic mechanisms of vacancy formation, diffusion, and aggregation, revealing the relationship between vacancy accumulation and void growth. It also accurately captures the effect of stress on vacancy aggregation. Using the Butler‐Volmer equation, the study explores the dynamic shrinkage of voids during the electrochemical stripping process at the interface. Based on this model, the synergistic effects of stacking force and external current on void formation and evolution are systematically examined. Additionally, high‐throughput phase‐field simulations, experimental validation, and machine learning techniques are employed to analyze void growth patterns in different electrolyte materials under varying operating conditions. The results show that in the Li‐LLZO system, void growth is primarily influenced by the combined effects of stacking pressure and current density, whereas in the Li‐Argyrodite system, stacking pressure plays a more dominant role. These findings deepen the understanding of void evolution in solid‐state batteries and provide a quantitative foundation for optimizing battery operation and enhancing interface stability.

Solid electrolytes encompass various types of nanodefects, including grain boundaries and nanovoids at the Li-metal/solid electrolyte interface, where lithium dendrite penetration has been extensively observed. Despite the importance of ion transport near grain boundaries with different anisotropy and the combinatorial effects with interfacial nanovoids, a comprehensive understanding of these phenomena has remains elusive. Here, we develop a chemo-electro-mechanical phase-field model to elucidate how Li penetrates Li7La3Zr2O12 in the co-presence of grain boundaries and interfacial nanovoids. The investigation unveils a grain-boundary-anisotropy-dependent behavior for Li-ion transport correlated with the presence of interfacial nanovoids. Notably, the Σ1 grain boundary exhibits faster Li dendrite growth, particularly in the co-presence of interfacial nanovoids. The model quantitatively reveals whether interfacial electronic properties dominate Li dendrite morphology and penetration, providing a strategy for designing stable Li/solid electrolyte interfaces. These findings help prioritize approaches for optimally tailoring nanodefects and exploiting synergetic effects at the interface to prevent dendrite formation. Grain boundary nanodefects exist in solid electrolytes but detailed factors affecting ion transport are still limited. Here, a chemo-electro-mechanical phase-field model shows how Li penetrates Li7La3Zr2O12 in the co-presence of grain boundaries and interfacial nanovoids

… Here, we present a modular phase-field modeling framework that is generally applicable to solid-state batteries with different electrodes and corresponding microstructures. The model …

… The commercialization of all-solid-state batteries (ASSBs) is … -mechanical phase-field model incorporating electrochemical … the design of durable, high-performance solid-state batteries. …

… batteries. However, the coupled mechanisms governing dendrite growth and crack propagation within solid-state … -mechanical coupled phase-field model designed to simulate the …

… the phase-field model will be discussed in Sect. 2 “Fundamentals of SSBs … phase-field modeling”. In specific, we will discuss the modeling strategy of electrochemical phase-field model …

Rechargeable batteries have a profound impact on our daily life so that it is urgent to capture the physical and chemical fundamentals affecting the operation and lifetime. The phase-field method is a powerful computational approach to describe and predict the evolution of mesoscale microstructures, which can help to understand the dynamic behavior of the material systems. In this review, we briefly introduce the theoretical framework of the phase-field model and its application in electrochemical systems, summarize the existing phase-field simulations in rechargeable batteries, and provide improvement, development, and problems to be considered of the future phase-field simulation in rechargeable batteries.

Modeling the effective ion conductivities of heterogeneous solid electrolytes typically involves the use of a computer-generated microstructure consisting of randomly or uniformly oriented fillers in a matrix. However, the structural features of the filler/matrix interface, which critically determine the interface ion conductivity and the microstructure morphology, have not been considered during the microstructure generation. Using nanoporous β-Li3PS4 electrolyte as an example, we develop a phase-field model that enables generating nanoporous microstructures of different porosities and connectivity patterns based on the depth and the energy of the surface (pore/electrolyte interface), both of which are predicted through density functional theory (DFT) calculations. Room-temperature effective ion conductivities of the generated microstructures are then calculated numerically, using DFT-estimated surface Li-ion conductivity (3.14 × 10-3 S/cm) and experimentally measured bulk Li-ion conductivity (8.93 × 10-7 S/cm) of β-Li3PS4 as the inputs. We also use the generated microstructures to inform effective medium theories to rapidly predict the effective ion conductivity via analytical calculations. When porosity approaches the percolation threshold, both the numerical and analytical methods predict a significantly enhanced Li-ion conductivity (1.74 × 10-4 S/cm) that is in good agreement with experimental data (1.64 × 10-4 S/cm). The present phase-field based multiscale model is generally applicable to predict both the microstructure patterns and the effective properties of heterogeneous solid electrolytes.

… Solid-state lithium metal batteries are one of the most … runaway of the solid-state lithium metal batteries. Though there are … –mechanical coupling phase-field model of lithium dendrite …

… All-solid-state Li metal batteries are widely considered as the … for the next generation of Li batteries. However, it is … In the present work, a multi-coupling phase field model of Li …

… phase field model to simulate dendrite growth and electrolyte crack expansion in solid-state … paper describes dendrite growth in solid-state electrolyte batteries as a two-dimensional …

Lithium (Li) dendrite growth poses serious challenges for the development of Li metal batteries. Replacing liquid electrolyte with solid composite electrolyte embedded with nanofiller additives can...

… knowledge from continuum scale simulations, eg, via phase field models [11,23–26] in order … A central part of phase field models is the energy density functional, a very basic one being …