Defect-enhanced selective ion transport in an ionic nanocomposite for efficient energy harvesting from moisture

Abstract

Moisture-based power generation technologies have received great attention in recent years. Although high output potential has been achieved, current systems suffer from the inability to continuously generate electricity with high power density for practical applications such as wearable and self-powered devices. Here, we report a moisture-sustained electric generator made from an ionic liquid (ILs) film supported by defect-engineered metal–organic frameworks (MOFs)/graphene oxide membranes. Our device can continuously generate power with an improved power density of up to 109.2 μW cm⁻² and an energy density of 31.45 J cm⁻² when placed under a humidity gradient. We ascribed the high performance to the retention effect of the defect-abundant MOFs membrane, which integrates high porosity and unpaired N-terminals to block the movement of cation clusters but allow the directional diffusion of moisture-liberated anions within the ILs, resulting in a sustainable anion/cation diode-like selective ion transport and improved charge separation for energy conversion.