Self-Healing Hydrogels Enabled by Ion Cross-Linking for Efficient Osmotic Energy Conversion

Three-dimensional (3D) hydrogel membranes offer great potential for harvesting osmotic energy from salinity gradients, yet their practical application remains limited by the lack of an autonomous self-healing capability, which is critical for long-term operational stability. Here, we report a self-healing 3D hydrogel membrane engineered via physical metal coordination interactions that enables efficient osmotic energy conversion with autonomous repair functionality. Combined experimental and theoretical investigations reveal that the space-charged 3D network facilitates highly efficient permselective ion transport. Beyond its excellent self-healing capability, the membrane delivers a high power density of 6.35 W m⁻² for osmotic energy harvesting from seawater-river water mixing, significantly outperforming most macroscopic porous nanofluidic membranes. This work not only underscores the potential of interconnected 3D hydrogels for high-performance osmotic energy conversion but also provides a practical strategy to achieve durable and sustainable energy harvesting systems.