Structural Topologies to Enable Exploitation of Grotthuss Diffusion for Fast Proton Ion Batteries

To date, a majority of battery technologies rely on metal-ion charge carriers. Surprisingly, non-metal cations, particularly proton-containing cations, i.e., H⁺ , H₃O⁺, and NH⁺⁴ , have received exceedingly little attention. The simplest form of hydrogen cation, a single proton, is nearly "invisible" with a measured radius of ∼0.89 fm or ∼2.1 fm, using muon or e⁻ spectroscopy, respectively. Due to the negligible strain of hosting protons, the rate capability and cycle life of proton batteries have the potential to be far superior to those of existing batteries. In this talk, I will describe the hierarchy of structural ingredients that permits fast proton transport and storage. These include a percolating nanoscale pipework containing a constrained network of hydrogen bonded water. We have abstracted topology of this bonding network as a graph and show that the network remains robust as it is filled with additional protons.