A high-current hydrovoltaic generator enabled by MXene/Al2O3 hybrid interfaces

Abstract

The growing demand for distributed energy systems and wearable electronics has spurred strong interest in hydrovoltaic technologies. However, the vast majority of metal oxide-based hydrovoltaic devices, with Al2O3 being a prime example, are typically limited by low current output due to inefficient internal charge extraction and transport. In this work, we report a high-performance hydrovoltaic generator (HEG) fabricated by sequentially depositing zero-dimensional Al2O3 nanoparticles and two-dimensional MXene nanosheets onto a porous cotton fabric (CF) substrate. This hybrid architecture harnesses the electrokinetic charge generation of Al2O3 while utilizing the metallic conductivity of MXene as an efficient charge-collection and transport network, thereby significantly reducing internal resistance. The resulting MXene/Al2O3@CF hydrovoltaic generator (MAHEG) exhibits a three-order-of-magnitude enhancement in short-circuit current compared with a pure Al2O3 device. Under ambient conditions, the MAHEG delivers a maximum power density output of 47.72 μW cm−2 (∼0.39 V, ∼611.8 μA) and maintains excellent stability over repeated wet–dry cycles. Moreover, multiple units can be integrated with nearly linear scalability in voltage and current through series and parallel configurations, enabling direct powering of low-power electronic devices.