MXene‐Boosted Imine Cathodes with Extended Conjugated Structure for Aqueous Zinc‐Ion Batteries

Organic molecules have been considered promising energy-storage materials in aqueous zinc-ion batteries (ZIBs), but are plagued by poor conductivity and structural instability because of the short-range conjugated structure and low molecular weight. Herein, an imine-based tris(aza)pentacene (TAP) with extended conjugated effects along the CN backbones is proposed, which is in situ injected into layered MXene to form a TAP/Ti3 C2 Tx cathode. Theoretical and electrochemical analyses reveal a selective H+ /Zn2+ co-insertion/extraction mechanism in TAP, which is ascribed to the steric effect on the availability of active CN sites. Moreover, Ti3 C2 Tx , as a conductive scaffold, favors fast Zn2+ diffusion to boost the electrode kinetics of TAP. Close electronic interactions between TAP and Ti3 C2 Tx preserve the structural integrity of TAP/Ti3 C2 Tx during the repeated charge/discharge. Accordingly, the TAP/Ti3 C2 Tx cathode delivers a high reversible capacity of 303 mAh g-1 at 0.04 A g-1 in aqueous ZIBs, which also realizes an ultralong lifetime over 10 000 cycles with a capacity retention of 81.6%. Furthermore, flexible Zn||TAP/Ti3 C2 Tx batteries with a quasi-solid-state electrolyte demonstrate potential application in wearable electronic devices. This work offers pivotal guidance to create highly stable organic electrodes for advanced ZIBs.