Maximizing Energy Efficiency of Porous Electrodes Via Topology Optimization

Conventional porous electrodes normally consist of homogeneous, unorganized collections of small-scale particles that offer little opportunity in terms of designing higher performance electrochemical devices. Indeed, simply increasing the surface area to maximize activity is usually detrimental to electrochemical transport because of increased tortuosity. Luckily, modern advanced and additive manufacturing methods present an opportunity for porous electrode structures that span length scales. In this presentation, we consider topology optimization as a tool to inform the design of porous electrodes. We introduce an optimization framework for a generic porous electrode model and apply it to two applications: an electrode driving a steady Faradaic reaction, and a transiently operated electrode in a supercapacitor. In each case, computationally designed electrodes that maximize energy efficiency are shown to outperform monolithic, homogeneous electrodes. For low effective ionic conductivity materials, the optimized designs exhibit hierarchical features with macropores that facilitate ionic transport.