Polycarbonyl conjugated porous polyimide as anode materials for high performance sodium-ion batteries

Abstract

Conjugated microporous polymers (CMPs) have attracted considerable attention as potential organic anode materials for sodium-ion batteries (SIBs) due to their flexible chemical structure, high porosity, environmental friendliness, and cost effectiveness. However, the inherent shortcomings of organic electrodes, such as low conductivity, high solubility in electrolyte, narrow material utilization, etc., limit their further development. In this work, we successfully prepared a novel porous polyimide PPD containing multicarbonyl active centers via the polycondensation of pyromellitic dianhydride (PMDA) and 2,6-diaminoanthraquinone (DAAQ). The stable conjugated structure and multiple redox centers give the polymer high reversible specific capacity (244.6 mAh/g after 100 cycles at 100 mA/g), ultra-long cycle stability (100.7 mAh/g after 2000 cycles at 1.0 A/g), and predominant rate capability. Meanwhile, the sodium storage mechanism of the electrode materials during the charging and discharging process is investigated by ex-situ XPS/FTIR analysis. Due to the exceptional electrochemical properties and simple synthesis method, this work may shed light on the preparation of polyimide-based anodes for high specific capacity and rate capability secondary batteries.