A High‐Capacity Semiconductor Organic Polymer for Stable Aqueous Ammonium‐Ion Storage

Abstract

AbstractIn aqueous ammonium‐ion storage (AAIS), effective hydrogen‐binding sites are crucial for designing high‐performance ammonium ions (NH4+) host materials. The organic small molecule tetraamino‐p‐benzoquinone (TABQ) shows great potential in AAIS due to its unique hydrogen‐bonding interactions with NH4+. However, such small‐molecule materials typically exhibit severe dissolution in aqueous electrolytes. Moreover, their low conductivity severely hampers their ability to store ammonium ions. To address these challenges concurrently, a chain amide polymer (PPAT) is designed by introducing a 3,4,9,10‐perylenetetracarboxylic dianhydride to extend the skeleton of TABQ. This polymer exhibits an ultralow solubility of 0.00058 mg mL−1 and introduces substantial functional groups for hydrogen‐bonding interactions. The conjugated effect is further extended by combining it with polyaniline (PANI). The spectral and computational results indicate that the designed material possesses an elevated HOMO energy level, a reduced LUMO energy level, and a smaller bandgap. The delocalization of electrons throughout the entire molecule leads to a semiconducting nature. The organic polymer electrode delivers a high capacity of 291.81 mAh g−1 at 1 A g−1, outperforming state‐of‐the‐art NH4+ storage organic materials. The energy storage mechanism of the hydrogen‐bonding interactions between the organic polymer and NH4+ is investigated, and the active sites that contribute to high capacity are identified.