Multifunctional Porous Organic Polymer Anode with Desired Redox Potential and Capacity for High-Performance Aqueous Sodium-Ion and Ammonium-Ion Batteries

Aqueous sodium-ion batteries (ASIBs) and aqueous ammonium-ion batteries (AAIBs) attract great attention due to their low cost, safety, and environmental friendliness, but the lack of suitable electrodes with competitive capacity and redox potential limits their practical applications. Herein, we report a porous organic polymer (POP) with multiple redox processes as anodes for ASIBs and AAIBs. This POP displays desired redox potential and shows high reversible capacity of more than 200 mAh g^-1 in both ASIBs and AAIBs. Full cells configured by this POP anode also display excellent performance (about 80% and 60% capacity retention over 1000 cycles in ASIBs and AAIBs). In addition, the intercalation chemistry of inorganic NH₄⁺ with this POP is investigated, illustrating that the pyrazine sites in this POP are the redox centers to reversibly combine with NH₄⁺. This work provides a promising and alternative anode for ASIBs and AAIBs and paves a new way for the development of novel organic materials for other aqueous battery systems.