Ultralong-Life Quinone-Based\nPorous Organic Polymer\nCathode for High-Performance Aqueous Zinc-Ion Batteries

Abstract

We synthesized and studied a redox-active quinone-based\nporous\norganic polymer (rPOP) and found ultralong cycle life: it is a promising\norganic cathode for aqueous zinc-ion batteries (ZIBs). It has high\nphysicochemical stability and enhanced intrinsic conductivity from\nits fused-aromatic conjugated skeleton. rPOP’s high porosity\nallows for efficient Zn²⁺ infiltration through the pores\nduring charging–discharging cycles and contributes to the efficient\nutilization of redox-active quinone units. It delivers a specific\ncapacity of 120 mAh g^–1 at a current density of\n0.1 A g^–1 with a flat and long discharge plateau,\nwhich is critically important to provide a stable voltage output.\nIt provides ultralong cycle life at a current density of 1.0 A g^–1 for 1000 and at 2.0 A g^–1 for 30 000\ncycles, with initial capacity retention of 95 and 66%, respectively.\nThe co-insertion (Zn²⁺ and H⁺) charge storage\nmechanism was investigated using various electrochemical measurements\nand ex/in situ structural characterization techniques, and is explained\nherein. These findings contribute to a better understanding of the\nstructure–property relationship for rPOP and open a new avenue\nfor new organic cathode materials for high-performance next-generation\naqueous batteries.