Abstract
High-voltage p-type organic cathodes are attracting broad attention for boosting zinc batteries, but are hindered by single-electron reactions and low utilization of redox sites due to high reaction energy barriers with incompatible anions. Here we design polyheterocycle organics (PHOs) via grafting dual-site-active phenothiazine and piperazine motifs to form donor-acceptor-extended structures which show multi-electron p-type redox reactions for superior anion storage. With the decrease in anionic Stokes radius and the increase in charge density (TFSI(-) → OTF(-) → SO(4) (2-)), SO(4) (2-) exhibits the strongest bipedal ion-pairing ability with PHOs during oxidation via an ultralow activation energy (0.20 vs. 0.38 eV of OTF(-) and 0.45 eV of TFSI(-)). This facilitates fast and full utilization of phenothiazine/piperazine active motifs by small-sized and doubly charged SO(4) (2-) anions (99.5% vs. 83.2% of OTF(-) and 58.1% of TFSI(-)). Consequently, the PHO cathode delivers superior SO(4) (2-)-storage energy density (317 Wh kg(-1)) and cycling lifespan (71.4% capacity retention over 100 000 cycles), surpassing OTF(-) (273 Wh kg(-1)/67.1%) and TFSI(-) storage (210 Wh kg(-1)/60.2%), as well as reported p-type organics. This work presents a new paradigm for designing multi-electron organics compatible with optimized anions for better zinc batteries.