A π-Bridge Spacer Embedded Electron Donor-Acceptor Polymer for Flexible Electrochromic Zn-Ion Batteries.

Abstract

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 throughthe cycles, providing extremely stable cyclability with high specific capacity (110 mAhg-1 ) at very fast rates (8 Ag-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 mAhg-1 at current density of 8 Ag-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.