Hydronium‐Ion Batteries with Perylenetetracarboxylic Dianhydride Crystals as an Electrode

Abstract We demonstrate for the first time that hydronium ions can be reversibly stored in an electrode of crystalline 3,4,9,10‐perylenetetracarboxylic dianhydride (PTCDA). PTCDA exhibits a capacity of 85 mAh g −1 at 1 A g −1 after an initial conditioning process. Ex situ X‐ray diffraction revealed reversible and significant structure dilation upon reduction of PTCDA in an acidic electrolyte, which can only be ascribed to hydronium‐ion intercalation. The lattice expansion upon hydronium storage was theoretically explored by first‐principles density functional theory (DFT) calculations, which confirmed the hydronium storage in PTCDA.