Options
Deformation and Stresses During Alkali Metal Alloying/Dealloying of Sn-Based Electrodes
Journal
Applied Mechanics Reviews
ISSN
00036900
Date Issued
2022-02-01
Author(s)
Gandharapu, Pranay
Mukhopadhyay, Amartya
Abstract
Enhancement of energy density and safety aspects of Li-ion cells necessitate the usage of "alloying reaction"-based anode materials in lieu of the presently used intercalationbased graphitic carbon. This becomes even more important for the upcoming Na-ion battery system since graphitic carbon does not intercalate sufficient Na-ions to qualify as an anode material. Among the potential "alloying reaction"based anode materials for Liion batteries and beyond (viz., Na-ion, K-ion battery systems), Si and Sn have received the major focus; with the inherently ductile nature of Sn (as against the brittleness of Si) and the considerably better stability in the context of electrochemical Na-/K-storage, of late, tilting the balance somewhat in favor of Sn. Nevertheless, similar to Si and most other "alloying reaction"-based anode materials, Sn also undergoes volume expansion/ contraction and phase transformations during alkali metal-ion insertion/removal. These cause stress-induced cracking, pulverization, delamination from current collector, accrued polarization and, thus, fairly rapid capacity fade upon electrochemical cycling. Unlike Si, the aforementioned loss in mechanical integrity is believed to be primarily caused by some of the deleterious first-order phase transformations and concomitant formation of brittle intermetallic phases during the alloying/de-alloying process. Against this backdrop, this review article focuses on aspects related to deformation, stress development and associated failure mechanisms of Sn-based electrodes for alkali-metal ion batteries; eventually establishing correlations between phase assemblage/transformation, stress development, mechanical integrity, electrode composition/architecture and electrochemical behavior.
Subjects