Energy storing bricks for stationary PEDOT supercapacitors

Fired brick is a universal building material, produced by thousand-year-old technology, that throughout history has seldom served any other purpose. Here, we develop a scalable, cost-effective and versatile chemical synthesis using a fired brick to control oxidative radical polymerization and deposition of a nanofibrillar coating of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). A fired brick’s open microstructure, mechanical robustness and ~8 wt% α-Fe2O3 content afford an ideal substrate for developing electrochemical PEDOT electrodes and stationary supercapacitors that readily stack into modules. Five-minute epoxy serves as a waterproof case enabling the operation of our supercapacitors while submerged underwater and a gel electrolyte extends cycling stability to 10,000 cycles with ~90% capacitance retention. Fired brick is a universal building material, produced by thousand-year-old technology, which throughout history has seldom served any other purpose. Here, the authors show that bricks can store energy after chemical treatment to convert their iron oxide content into conducting polymer nanofibers.