An aqueous Al–PbO2 battery with pH-gradient engineering surpasses 3.5 V

Abstract

An aqueous Al–PbO₂ hybrid battery surpasses the electrochemical stability of water through a pH-gradient design, achieving 3.52 V, 914 mW cm⁻² power density, and 11.85 mAh cm⁻² capacity. A decoupled charging process further enables energy-efficient operation with hydrogen generation, establishing a high-voltage and multifunctional aqueous energy platform.