Three-dimensional conductive copper–organic framework with a dual-redox center for high-performance aqueous zinc batteries

Abstract

Metal–organic frameworks (MOFs) are promising cathode materials for aqueous zinc-ion batteries (ZIBs) in view of their tunable molecular structures, high porosity, and cost-effectiveness. However, their applications are severely hindered by the inferior structure stability, low conductivity, and limited number of redox-active centers. Here, we well-design a three-dimensional (3D) conductive copper–organic framework (Cu-TAPT) cathode material with dual electroactive sites for high-performance ZIBs. The Cu-TAPT cathodes are composed of in-plane one-dimensional π-d conjugated chains and strong π–π interactions between adjacent chains, which are further bridged by another column of stacked chains by tetrahedral coordination to form an extended 3D structure. The redox chemistry of both Cu²⁺ ions and conjugated carbonyl of Cu-TAPT cathodes achieves reversible Zn²⁺/H⁺ synergistic storage. As a result, the Cu-TAPT cathode delivers a high reversible capacity of 273.1 mAh g⁻¹ at 0.1 A g⁻¹, superior rate performance, and a high capacity retention over 75% after 1000 cycles. This work will provide a new philosophy to design advanced organic materials for aqueous ZIBs and beyond.