Engineering Scale Simulation of Nonequilibrium Network Phases for Battery Electrolytes

摘要

Diblock copolymers play an important role in the fabrication of battery materials and fuel cells. For these applications, one block provides mechanical stability, whereas the other is conducting. The application characteristics of the material critically depend on the morphology of the multicomponent material, and three-dimensional, percolating domains of the conducting domains are preferred. In this work, we investigate the nonequilibrium morphology of diblock copolymers after a quench from the disordered phase. After the spinodal self-assembly, we observe three-dimensionally percolating network structures for volume fractions, f >= 8/32, of the conducting component even if the equilibrium phases exhibit different percolation properties. We quantify the conductivity and tortuosity of these structures via a simple random-walk model and observe that the conductivity of the nonequilibrium structures is significantly smaller than that of the equilibrium phases. We also find large but finite-sized, fractal-like structures inside the morphology, which influence the transport properties. To explore the morphology on different scales and mitigate finite-size effects, we employ very large simulations with billions of particles. Our work demonstrates that for the prediction of bulk transport properties in these nonequilibrium morphologies it is necessary to study such large system sizes.