Abstract
Operation of energy storage and conversion devices is ultimately controlled by series of intertwined ionic and electronic transport processes and electrochemical reactions at surfaces and interfaces,
strongly mediated by strain and mechanical processes [1-4]. In a typical fuel cell, these include
chemical species transport in porous cathode and anode materials, gas-solid electrochemical
reactions at grains and triple-phase boundaries (TPBs), ionic and electronic flows in multicomponent
electrodes, and chemical and electronic potential drops at internal interfaces in electrodes
and electrolytes. All these phenomena are sensitively affected by the microstructure of materials
from device level to the atomic scales as illustrated in Fig. 1. Similar spectrum of length
scales and phenomena underpin operation of other energy systems including primary and secondary
batteries, as well as hybrid systems such flow and metal-air/water batteries.
