Laser-Induced Graphene-Enabled Programmable Ion-Gradient Composites for Hundred-Hour-Stable, High-Power Moisture-Electric Generation Toward Self-Sustaining IoT Systems.

Moisture-electric generators (MEGs) are emerging as promising green power sources for distributed micro-devices. However, achieving stable and reproducible electrical output remains a major challenge, largely due to the lack of a unified material platform that allows systematic control over ion-gradient design. Herein, a novel composite-engineering strategy is proposed that integrates proton- and anion-doped polybenzimidazole (PBI) with a hydrophilic, laser-induced graphene (LIG) electrodes in a single-step fabrication process. This approach provides the tailored construction of both mono-ionic and hetero-ionic gradient configurations within the same polymer system, offering a compatible platform to decipher the relationships between ion concentration and bilayer structure for device performance. The optimized MEG delivers a high short-circuit current density of 1 mA cm- 2, a maximum power density of 43.3 µW cm- 2, and an integrated open-circuit voltage up to 6.26 V. Crucially, scalable MEG arrays maintain a stable output of 2 V and 1 µA cm-2 after 5 days of continuous operation, demonstrating exceptional long-term stability. Optimized MEGs (arrays) can further power electronics and sense humidity, enabling self-sustaining water-electric cycling for autonomous IoT systems. This work establishes a material-level design framework for high-performance, durable moisture-driven energy generation.