Abstract 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.
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Toward High-Capacity Battery Anode Materials: Chemistry and Mechanics Intertwined
Lithium metal and lithium-rich alloys are high-capacity anode materials that could boost the energy content of rechargeable batteries. However, their development has been hindered by rapid capacity decay during cycling, which is driven by the substantial structural, morphological, and volumetric transformations that these materials and their interfaces experience during charge and discharge. During these transformations, the interplay between chemical/structural changes and solid mechanics plays a defining role in determining electrochemical degradation. This Perspective discusses how chemistry and mechanics are interrelated in influencing the reaction mechanisms, stability, and performance of both lithium metal anodes and alloy anodes. Battery systems with liquid electrolytes and solid-state electrolytes are considered because of the distinct effects of chemo-mechanics in each system. Building on this knowledge, we present a discussion of emerging ideas to control and mitigate chemo-mechanical degradation in these materials to enable translation to commercial systems, which could lead to the development of high-energy batteries that are urgently needed to power our increasingly electrified world.
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- Award ID(s):
- 1652471
- NSF-PAR ID:
- 10197976
- Date Published:
- Journal Name:
- Chemistry of Materials
- ISSN:
- 0897-4756
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.chemmater.0c02981
