A critical part of fuel cells and batteries is the electrolyte. Commonly used liquid electrolytes are bulky, prone to shorts, and can pose a fire or explosion risk. Researchers are developing a new solid polymer electrolyte (SPE) that can solve these problems while improving battery performance.

The disordered structure of Nafion, left, means the path protons take through the electrolyte is hard to predict or control. The researchers’ new structure, right, provides a straighter path. (Nafion illustration adapted from Kreuer. J., Membr. Sci. 2001, 185, 29–39, Fig. 2)

The SPE Nafion, which is widely used in proton-exchange membrane fuel cells, is a sheet of flexible plastic permeable to protons and impermeable to electrons. However, it is hard to study because its structure is random and disordered. The new SPE is twice as fast as Nafion and is projected to do even better with future improvements. Cellphone batteries made with this SPE could be thinner and safer.