Zinc-ion batteries (ZIBs) have drawn much attention for next-generation energy storage for smart and wearable electronics due to their high theoretical gravimetric/volumetric energy capacities, safety from explosive hazards, and cost-effectiveness. However, current state-of-the-art ZIBs lack the energy capacity necessary to facilitate smart functionalities for intelligent electronics. In this work, a "π-bridge spacer"-embedded electron donor-acceptor polymer cathode combined with a Zn2+ -ion-conducting electrolyte is proposed for a smart and flexible ZIB to provide high electrochromic-electrochemical performances. The π-bridge spacer endows the polymeric skeleton with improved physical ion accessibility and sensitive charge transfer through the cycles, providing extremely stable cyclability with high specific capacity (110 mAh g-1 ) at very fast rates (8 A g-1 ) and large coloration efficiency (79.8 cm2 C-1 ) under severe mechanical deformation over a long period. These results are markedly outstanding compared to the topological analogue without the π-bridge spacer (80 mAh g-1 at current density of 8 A g-1 , 63.0 cm2 C-1 ). The design to incorporate a π-bridge spacer realizes notable electrochromism behaviors and high electrochemical performance, which sheds light on the rational development of multifunctional flexible-ZIBs with color visualization properties for widespread usage in powering smart electronics.
Keywords: electrochromic Zn-ion batteries; electron donor-acceptor polymers; flexible devices; gel polymer electrolyte; smart energy storage; π-bridge spacer.
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