Tailored Hierarchical Porous Carbon through Template Modification for Antifreezing Quasi‐Solid‐State Zinc Ion Hybrid Supercapacitors

Aqueous zinc ion hybrid supercapacitors (ZHSCs) have emerged and are regarded as promising candidates for energy storage due to their environmental friendlessness and cost‐effectiveness. However, the development of a satisfying positive electrode with high performance still poses challenges. Herein, a hierarchical porous carbon with a fast‐ion‐transport feature is rationally reported via a facile template modification strategy. By adjusting the content of the template, the physiochemical characteristics and microstructures of carbon can be reasonably optimized. As proof of concept, the produced carbon electrode can deliver a high specific capacitance of 294.8 F g−1 at a current density of 0.2 A g−1, long cycling stability with ≈100% capacitance retention over 20 000 cycles, and a maximum power density of 13.2 kW kg−1 at 30.8 W h kg−1. Significantly, a superior areal capacitance of 3390 mF cm−2 is offered with a mass loading of 21 mg cm−2. When coupled with a unique antifreezing hydrogel electrolyte, the constructed quasi‐solid‐state ZHSC can not only endure −15 °C, but also exhibits outstanding durability and an ultralow self‐discharging rate, demonstrating its potential prospect for extreme conditions. This work may bring light on the preparation of carbon materials and the fabrication of multifunctional devices