Multiscale modeling of electrolytes in porous electrode: From equilibrium structure to non-equilibrium transport

Abstract

Understanding the mechanisms and properties of various transport processes in the electrolyte, porous electrode, and at the interface between electrode and electrolyte plays a crucial role in guiding the improvement of electrolytes, materials and microstructures of electrode. Nanoscale equilibrium properties and nonequilibrium ion transport are substantially different to that in the bulk, which are difficult to observe from experiments directly. In this paper, we introduce equilibrium and no-equilibrium thermodynamics for electrolyte in porous electrodes or electrolyte–electrode interface. The equilibrium properties of electrical double layer (EDL) including the EDL structure and capacitance are discussed. In addition, classical non-equilibrium thermodynamic theory is introduced to help us understand the coupling effect of different transport processes. We also review the recent studies of nonequilibrium ion transport in porous electrode by molecular and continuum methods, among these methods, dynamic density functional theory (DDFT) shows tremendous potential as its high efficiency and high accuracy. Moreover, some opportunities for future development and application of the non-equilibrium thermodynamics in electrochemical system are prospected.