Low-Cost and ion-selective membranes are required to meet the growing demands for peak performance by next-generation batteries for EVs, aviation, and the grid. To that end, I will showcase a highly disruptive membrane platform based on polymers of intrinsic microporosity, whose pores are on the length scale of solvated ions and small molecules that are sometimes used as the battery’s active materials (e.g., as in flow batteries). The design space for these polymer membranes is advanced using a variety of computational tools, including computational materials genomics. The foundational knowledge built using these tools provides a roadmap for the diversity-oriented synthetic development of polymer membranes with specific pore architectures and chemistry, specifically tailored for the battery’s chemistry. I will also outline foundations on which to build adaptive membranes, where judiciously placed molecular switches allow for the membrane’s transport properties to be modulated in-situ in response to excursions that are otherwise detrimental to the battery’s cycle-life. There remains much to be learned about the origins of their adaptive and dynamic properties, and how these feed back across multiple length and timescales in the electrochemical cell.