Applied Mechanics Reviews (AMR) was founded in 1948 under the editorship of Lloyd Hamilton Donnell (1895–1997), in whose honor the biennial Lloyd Hamilton Donnell Applied Mechanics Reviews Paper Award was inaugurated in 2014. The founding of the journal, shortly after World War II, filled a void in the review of state-of-the-art research in applied mechanics, occupied before the war by the German periodical Zeitschrift für Mechanik. The inaugural volume included both Theodore von Karman and Stephen Timoshenko as Editorial Advisors.
Over the years, the scope and purpose of AMR evolved. This reflected the changing nature of scientific research in the engineering sciences, the diversification of journal publications, and the development of alternative mechanisms for disseminating research among geographically distributed groups. Today, the journal aims to provide long-shelf-life, state-of-the-art survey articles, and retrospective reviews across all relevant subdisciplines of applied mechanics and engineering science, including fluid and solid mechanics, heat transfer, dynamics and vibration, and applications. Importantly, papers published in AMR emphasize added value beyond what is available in the existing literature. They do so through authoritative commentary and original synthesis, relating and contrasting the authors' original contributions to those of the community.
Since 2014, a handful of AMR issues have been dedicated to collaboration with other ASME technical journals to feature significant contributions for a specific discipline in a single issue. Such special issues have aimed to bring to the fore topics of interest to the broader community as well as experts in the discipline, thereby inviting cross-disciplinary collaboration and welcoming new entrants to the field. Past collaborations include with the ASME Journal of Pressure Vessel Technology and the ASME Journal of Vibration and Acoustics in 2014; the ASME Journal of Tribology in 2017; the ASME Journal of Mechanisms and Robotics in 2018; and the ASME Journal of Computational and Nonlinear Dynamics in 2019.
The November 2022 and January 2023 issues of AMR constitute the final installment in the series of such collaborations overseen by Harry Dankowicz, who finished his term as Editor-in-Chief in September 2022. These issues developed together with the ASME Journal of Electrochemical Energy Conversion and Storage (JEECS) feature four review papers exemplifying state-of-the-art research in the mechanics of electrochemical energy conversion and storage. A companion Special Section on the Mechanics of Electrochemical Energy Conversion and Storage appeared in the November 2021 issue of JEECS and collected eight shorter papers reporting on original technical research with a similar focus [1].
Originally founded in 2004 as the ASME Journal of Fuel Cell Science and Technology and known by its new name since 2016, JEECS serves as a medium for rapid dissemination of original research results focused on processes, components, devices, and systems that store and convert electrical and chemical energy. The journal is a forum for research concerned with advanced materials development, synthesis, manufacturing, and characterization, as well as component, device, and systems design and analysis, with an interest in studies of reliability, durability, and damage tolerance. Areas of application include batteries, fuel cells, electrolyzers, separation membranes, electrochemical capacitors, thermogalvanic cells, and photo-electrochemical cells.
The four featured reviews in the November 2022 and January 2023 issues of AMR are all concerned with rechargeable battery technologies. They focus on the interplay of mechanics and electrochemistry in driving a deterioration of battery capacity during repeated cycles of charging and discharging, as well as on phenomena that may induce mechanical and (catastrophic) electrochemical failure.
In the work by Gandharapu and Mukhopadhyay (AMR 74(6), November 2022), the authors review causes of stress development and mechanical failure of Sn-based electrodes for future Li-, Na-, and K-ion batteries that rely on cycles of alloying/de-alloying for operation, in contrast to the reversible hosting of Li ions in graphitic carbon-based anodes through intercalation. This review is motivated by growing interest in the use of anode materials with higher storage capacity and reaction potentials well above the Li plating/stripping potential, as well as the use of alternative alkali metals that are more plentiful than lithium, viz., sodium and potassium. The discussion highlights the occurrence during alloying/de-alloying with Sn of sequences of intermetallic phases with different material properties than the parent material. The associated phase transformations produce dramatic volume changes and discontinuities between different material phases that result in stress development, plastic deformation, fracture, and disintegration/pulverization. The paper reviews empirical results on strategies for suppressing the deleterious effects of these phase transformations, including by reducing characteristic length scales to nanoscale dimensions, inserting interlayers of inactive components to accommodate volume changes and maintain conductivity even if the active materials disintegrate, and/or pre-alloying with other inactive or active elements to buffer against dimensional changes and modify reaction pathways. As articulated by the authors, while significant material science developments surely lie in store for these next-generation battery technologies, significant benefits accrue from a fundamental understanding of the coupling between electrochemistry and mechanics.
This challenge is explored in greater depth by Gao et al. (AMR 74(6), November 2022), which focuses on anodes made from C, Si, SiOx, and Si/C composite, and reviews the state of the art in theoretical and computational modeling of stress development during electrochemical cycling, as well as experimental characterization of related failure modes. Modes considered in the discussion include cracks on the surface of Si particles, cracks of the carbon shells of Si/C particles that lead to formation of inactive particles after repeated cycling, and cracks within the active layer that destroy the overall electrochemical network; debonding failures between the core and shell of Si/C particles or between active particles and binders that increase interface impedances, and between active layers and the current collector that result in loss of electrical contact; as well as the formation of Li dendrites that may penetrate the solid electrolyte and lead to dangerous short circuits and thermal run-away. The authors further provide a comprehensive survey of stress-management strategies in Si-based high-capacity anodes like those presented for Sn-based anodes by Gandharapu and Mukhopadhyay. In their conclusions, and in describing recent modeling work by the authors and others, they stress the need for multiscale-multiphysics models of the full electrochemomechanical coupling at both particle and electrode levels.
The detailed review by Deshpande and McMeeking (AMR 75(1), January 2023) puts an even greater emphasis on efforts to model the combined effects of mechanics, electrochemistry, thermodynamics, and kinetics on phenomena that affect the performance of solid-state batteries with metal anodes. Their discussion provides authoritative commentary on the foundational literature and explores simplified theoretical models and back-of-the-envelope predictions for several relevant phenomena, including the onset of defect-initiated delamination at the interface between the solid electrolyte and a cathode storage particle, crack propagation in the solid electrolyte, and lithium-ion transport in solid electrolytes. The authors review theoretical foundations underlying different reported extensions to the Butler-Volmer equation for redox reactions at the electrolyte/electrode interfaces with emphasis on the influence of mechanical stress. They go on to apply the results to quantitative predictions about possible unstable growth of roughness of a lithium metal anode during charging, as well as the existence of a critical roughness wavelength beyond which growth occurs. A final section investigates models of nucleation and growth of lithium filaments through solid electrolytes and highlights the need to account for the presence of voids at the electrode/electrolyte interface that drive an increased rate of filament growth. In their conclusions, the authors point to several factors requiring further elucidation, including the effects of creep deformation and the processes leading to the formation of large voids.
The need for foundational contributions at the intersection of mechanics and electrochemistry is also stressed in the state-of-the-art review by Naik et al. (AMR 75(1), January 2023) on the stability of solid–liquid and solid-solid interfaces in lithium metal batteries. A recurrent theme throughout the discussion is that of heterogeneity—whether in surface morphology, microstructure, material properties, electrochemistry, or percolation pathways, or a result of asymmetric contact loss—and the implications to different failure modes. For example, in a section dedicated to solid state lithium-sulfur batteries, the authors stress the need to consider the effects on transport and reaction kinetics of stress heterogeneity arising from nonuniform lithium-sulfide deposition. Transport and reaction heterogeneities are also called out as playing a critical role in the loss of stability of the solid-electrolyte interphase layer between lithium metal electrodes and liquid electrolyte over multiple charging and discharging cycles. In solid state batteries, surface roughness and microstructural defects are found to cause localized nucleation during lithium plating and contact loss during stripping. Solid-solid point contacts between cathode active materials and solid electrolyte are shown to lead to stress concentrations, current focusing, and localized overpotential. Despite extensive ongoing research into minimizing such heterogeneities, it is clear from this paper that much fundamental work remains.
By collecting these papers in two issues of AMR, we hope to bring attention to a fertile area of collaboration between theoretical and experimental mechanicians, material scientists, and electrochemists, one that is vital for modern life and for a future of sustainable technologies and energy utilization. Although the subject matter is presented here at a level of sophistication appropriate for state-of-the-art survey papers, we also hope that some of the content may be used to interest new generations of engineers and scientists in interdisciplinary work grounded in a combination of first principles, cutting-edge experiments, and advanced technologies.
