Heterogeneous Side‐Chain Polymers Provide High‐Speed Migration Pathways for Li ⁺ in Ionogels, Enabling High‐Performance Infrared Electrochromic Supercapacitors

ABSTRACT Efficient Li + transport is essential for achieving high‐performance ionogel polymer electrolytes (IPEs). However, in the IPEs, Li + transport is severely hindered by strong coordination with the anions of ionic liquids and polymer segments. Here, we propose a polymeric heterogenous side‐chain strategy that selectively accelerates Li + migration in IPEs. The flexible and polar side chains provided by 2‐(2‐Ethoxyethoxy)ethyl acrylate coordinate with Li + , effectively releasing Li + from [Li(anion) n ] −(n−1) clusters, while another positively charged side chains mitigate Li + –polymer interactions, further promoting Li + mobility. These dual‐function polymers prevent Li + from becoming trapped within [Li(anion) n ] −(n−1) clusters and facilitate rapid hopping transport of Li + with minimal resistance at polymer sites, ultimately enabling efficient Li + transport. As a result, the IPEs exhibit enhanced high Li + transference number (0.6) and ionic conductivity (4.6 mS cm − 1 ). Benefiting from enhanced Li + transport of IPEs, infrared electrochromic supercapacitors (IR‐EC‐SC) exhibit outstanding IR electrochromic performance (0.45, 8–14 µm) and energy storage capabilities (222.3 F g −1 , 1A g −1 ). In addition, the IR‐EC‐SC exhibits rapid response times and remains operational after 15 000 cycles. This work demonstrates new insights into the regulation of Li + transport in IPEs, offering a promising pathway toward high‐performance IR‐EC‐SC for advanced thermal management, smart optical applications, and energy storage applications.