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The development of next-generation batteries, utilizing electrodes with high capacities and power densities requires a comprehensive understanding and precise control of material interfaces and architectures. Electro-chemo-mechanics plays an integral role in the morphological evolution and stability of such complex interfaces. Volume changes in electrode materials and the chemical interactions of electrode/electrolyte interfaces result in nonuniform stress fields and structurally different interphases, fundamentally affecting the underlying transport and reaction kinetics. The origin of this mechanistic coupling and its implications on degradation is uniquely dependent on the interface characteristics. In this review, the distinct nature of chemo–mechanical coupling and failure mechanisms at solid–liquid interfaces and solid–solid interfaces is analyzed. For lithium metal electrodes, the critical role of surface/microstructural heterogeneities on the solid electrolyte interphase (SEI) stability and dendrite growth in liquid electrolytes, and on the onset of contact loss and filament penetration with solid electrolytes is summarized. With respect to composite electrodes, key differences in the microstructure-coupled electro-chemo-mechanical attributes of intercalation- and conversion-based chemistries are delineated. Moving from liquid to solid electrolytes in such cathodes, we highlight the significant impact of solid–solid point contacts on transport/mechanical response, electrochemical performance, and failure modes such as particle cracking and delamination. Finally, we present our perspective on future research directions and opportunities to address the underlying electro-chemo-mechanical challenges for enabling next-generation lithium metal batteries.

A pouch cell method for retesting double-sided electrodes harvested from commercial lithium-ion batteries in a 3-electrode cell arrangement has been developed. By relying on pressure from restraint plates to make tab electrical connections, this method (1) requires no welding, (2) does not require a dry room, (3) does not require precision sealing equipment inside of an inert-gas glove box, and (4) does not require removal of composite material off of one side of the electrode which may compromise the composite to be tested on the other side. Lithium chips pressed onto copper mesh serve as the reference and counter electrodes and the electrolyte used was 1.0 M LiPF6 1:1 ethylene carbonate (EC):Diethyl carbonate (DEC) v/v. Electrochemical cycling of electrodes from a commercial 3.6 Ah 18650 lithium-ion cell demonstrated cell function and showed stable capacity and potential charge/discharge profiles after two cycles for the cathode and four cycles for the anode. The areal capacity of the anode and cathode was determined to be 5.50 ± 0.31 and 5.50 ± 0.30 mAh/cm2, respectively, based on a potential range of 0.005–1.5 V versus Li/Li+ for the anode and 3.0–4.25 V versus Li/Li+ for the cathode. High frequency, 500 kHz impedance measurements of the anode and cathode cells shows a real impedance of 1.55 Ohms and 2.17 Ohms, respectively, which is similar to prior studies on pouch cells with continuous tabs of similar capacity.

The shuttle effect and poor conductivity of the discharge products are among the primary impediments and scientific challenges for lithium–sulfur batteries. The lithium–sulfur battery is a complex energy storage system, which involves multistep electrochemical reactions, insoluble polysulfide precipitation in the cathode, soluble polysulfide transport, and self-discharge caused by chemical reactions between polysulfides and Li metal anode. These phenomena happen at different length and time-scales and are difficult to be entirely gauged by experimental techniques. In this paper, we reviewed the multiscale modeling studies on lithium–sulfur batteries: (1) the atomistic simulations were employed to seek alternative materials for mitigating the shuttle effect; (2) the growth kinetics of Li2S film and corresponding surface passivation were investigated by the interfacial model based on findings from atomistic simulations; (3) the nature of Li2S2, which is the only solid intermediate product, was revealed by the density functional theory simulation; and (4) macroscale models were developed to analyze the effect of reaction kinetics, sulfur loading, and transport properties on the cell performance. The challenge for the multiscale modeling approach is translating the microscopic information from atomistic simulations and interfacial model into the meso-/macroscale model for accurately predicting the cell performance.

Particle size plays an important role in the electrochemical performance of cathodes for lithium-ion (Li-ion) batteries. High energy planetary ball milling of LiNi1/3Mn1/3Co1/3O2 (NMC) cathode materials was investigated as a route to reduce the particle size and improve the electrochemical performance. The effect of ball milling times, milling speeds, and composition on the structure and properties of NMC cathodes was determined. X-ray diffraction analysis showed that ball milling decreased primary particle (crystallite) size by up to 29%, and the crystallite size was correlated with the milling time and milling speed. Using relatively mild milling conditions that provided an intermediate crystallite size, cathodes with higher capacities, improved rate capabilities, and improved capacity retention were obtained within 14 μm-thick electrode configurations. High milling speeds and long milling times not only resulted in smaller crystallite sizes but also lowered electrochemical performance. Beyond reduction in crystallite size, ball milling was found to increase the interfacial charge transfer resistance, lower the electrical conductivity, and produce aggregates that influenced performance. Computations support that electrolyte diffusivity within the cathode and film thickness play a significant role in the electrode performance. This study shows that cathodes with improved performance are obtained through use of mild ball milling conditions and appropriately designed electrodes that optimize the multiple transport phenomena involved in electrochemical charge storage materials.

Understanding interfacial phenomena such as ion and electron transport at dynamic interfaces is crucial for revolutionizing the development of materials and devices for energy-related applications. Moreover, advances in this field would enhance the progress of related electrochemical interfacial problems in biology, medicine, electronics, and photonics, among others. Although significant progress is taking place through in situ experimentation, modeling has emerged as the ideal complement to investigate details at the electronic and atomistic levels, which are more difficult or impossible to be captured with current experimental techniques. Among the most important interfacial phenomena, side reactions occurring at the surface of the negative electrodes of Li-ion batteries, due to the electrochemical instability of the electrolyte, result in the formation of a solid-electrolyte interphase layer (SEI). In this work, we briefly review the main mechanisms associated with SEI reduction reactions of aprotic organic solvents studied by quantum mechanical methods. We then report the results of a Kinetic Monte Carlo method to understand the initial stages of SEI growth.

Lithium-ion batteries are the most commonly used portable energy storage technology due to their relatively high specific energy and power but face thermal issues that raise safety concerns, particularly in automotive and aerospace applications. In these environments, there is zero tolerance for catastrophic failures such as fire or cell rupture, making thermal management a strict requirement to mitigate thermal runaway potential. The optimum configurations for such thermal management systems are dependent on both the thermo-electrochemical properties of the batteries and operating conditions/engineering constraints. The aim of this study is to determine the effect of various combined active (liquid heat exchanger) and passive (phase-change material) thermal management techniques on cell temperatures and thermal balancing. The cell configuration and volume/weight constraints have important roles in optimizing the thermal management technique, particularly when utilizing both active and passive systems together. A computational modeling study including conjugate heat transfer and fluid dynamics coupled with thermo-electrochemical dynamics is performed to investigate design trade-offs in lithium-ion battery thermal management strategies. It was found that phase-change material properties and cell spacing have a significant effect on the maximum and gradient of temperature in a module cooled by combined active and passive thermal management systems.

The lithium-ion battery (LIB) electrode represents a complex porous composite, consisting of multiple phases including active material (AM), conductive additive, and polymeric binder. This study proposes a mesoscale model to probe the effects of the cathode composition, e.g., the ratio of active material, conductive additive, and binder content, on the electrochemical properties and performance. The results reveal a complex nonmonotonic behavior in the effective electrical conductivity as the amount of conductive additive is increased. Insufficient electronic conductivity of the electrode limits the cell operation to lower currents. Once sufficient electron conduction (i.e., percolation) is achieved, the rate performance can be a strong function of ion-blockage effect and pore phase transport resistance. Even for the same porosity, different arrangements of the solid phases may lead to notable difference in the cell performance, which highlights the need for accurate microstructural characterization and composite electrode preparation strategies.