Electro-chemo-mechanical charge carrier equilibrium at interfaces
Journal
Physical Chemistry Chemical Physics
Journal Volume
23
Journal Issue
41
Pages
23730-23740
Date Issued
2021
Author(s)
Abstract
Electrochemical interfaces involving solids enable charge transfer, electrical transport, and mass storage in energy devices. One central concept that determines the interfacial charge carrier concentration is the space-charge field. The classical theory accounts for electrochemical equilibrium in the absence of mechanical effects; such effects have recently been found critical in many solids, such as materials for lithium-ion and solid-state batteries, perovskite solar cells, and fuel cells. Towards elucidating the interplay between charge carriers and mechanics, we establish a generalized electro-chemo-mechanical space-charge model and categorize the carriers into physically-meaningful four types, based on the signs of the charge number (i.e., polarity) and the partial molar volume (i.e., expansion coefficient). Beyond the electrostatic effects discussed in the literature, our work reveals the importance of elastic effects, as demonstrated by simulations of a composite beam bending experiment. The analysis highlights opportunities to systematically tune the interfacial electrical conductivity and the reaction kinetics of solids through mechanics. Our treatment provides a rational basis for understanding stress-driven phenomena at interfaces in a wide range of solids. ? 2021 the Owner Societies.
Subjects
Carrier concentration
Charge transfer
Fuel cells
Lithium-ion batteries
Reaction kinetics
Solid electrolytes
Solid state devices
Charge carrier concentrations
Classical theory
Electrical transport
Electrochemical interface
Electrochemicals
Energy devices
Interfacial charge
Mass storage
Mechanical
Space charge field
Perovskite
SDGs
Type
journal article