Hydrogen bonding-stabilized bipolar organic cathode achieved all-round enhancement in zinc batteries

Abstract

Bipolar organic small molecules with dual advantages of n/p-type redox reactions can achieve high-capacity-voltage zinc-organic batteries (ZOBs), but are plagued by inevitable dissolution in aqueous electrolytes. Here a hydrogen bonding-stabilized bipolar quinacridone (QA) molecule with synergetic coupling effects of two redox-active centers of n-type carbonyl moieties and p-type amine sites is proposed towards superior ZOBs. Compared with unipolar organics, bipolar QA molecule delivers low-energy-barrier redox kinetics and strong resistance to dissolution in aqueous electrolytes to avoid capacity decay due to the stable H-bond structure and extended π-conjugated aromatic plane. Consequently, Zn||QA battery harvests a high capacity of 212 mAh g⁻¹ at 0.2 A g⁻¹, an outstanding energy density (161 Wh kg⁻¹), along with superior electrochemical stability (20,000 cycles). The high-kinetics hybrid anion-cation two-electron co-coordination mechanism in QA cathode is the root of excellent electrochemical metrics. This study opens novel insights to design multielectron bipolar cathodes for high-performance ZOBs.