Universal thiourea coupling enhances electron and ion transport in quinone cathodes for aqueous zinc batteries

Organic electrode materials, despite their elemental abundance, environmental friendliness, and design flexibility, often suffer from limited electronic and ionic conductivities, which restrict their practical applications. Here, we present a universal thiourea coupling strategy that improves both electron and ion transport in quinone-based organic electrodes. Taking phenanthrenequinone as a representative example, thiourea incorporation increases the electron density of the quinones and improves the overall electronic conductivity of the electrode material. Meanwhile, thiourea establishes continuous proton-transport pathways, enabling proton-dominated redox reactions via a Grotthuss-type hopping mechanism. As a result, zinc batteries employing the coupled electrode exhibit stable cycling behavior over 6000 cycles at a low conductive carbon content (10 wt%) and maintain reliable operation in pouch-cell configurations under high mass loading conditions of 20 mg cm^-2. In addition, the applicability of this molecular coupling strategy is demonstrated across multiple quinone systems, paving that path towards practical organic electrode materials.