Polymer of intrinsic microporosity (PIM) films and membranes in electrochemical energy storage and conversion: A mini-review

Polymers of intrinsic microporosity (or PIMs) have emerged as practical film or membrane materials for a range of electrochemical technologies. Fundamentally, PIMs are based on highly rigid polymer backbone structures, which are inefficient for packing into solid films or structures. Poor packing in the solid is linked directly to (i) good solubility and processability, (ii) to glassy structures with persistent microporosity, (iii) to interesting permeation and separation properties for ions and for neutral molecular species, and (iv) to pore retention during pyrolysis. Further modification by cross-linking, introduction of charged functional groups, and hybrid material formation has been reported for applications in batteries, capacitors, fuel cells, and flow energy storage systems. This mini-review highlights recent applications suggested for PIMs in electrochemical energy systems.