Single Mesopores with High Surface Charges as Ultrahigh Performance Osmotic Power Generators

Numerous studies on osmotic power generators with nanoscale pores are conducted. However, their performance output is limited because of the finite osmotic current and conductance from such tiny pores. Here, a proof-of-concept study demonstrating that the rectified mesopore (sub-micrometer-scale pore) with high surface charges can be applied in osmotic energy conversion is reported. A single conical mesopore of ≈405 nm in tip diameter, which can reach an osmotic conductance as high as 0.284 μS (corresponding to a current of 27.5 nA and voltage of 97 mV), enables a record-high power of 667 pW under a 1000-fold salinity gradient, more than doubling all of the state-of-the-art single-pore osmotic power generators reported. This work extends the knowledge of osmotic energy with solid-state pores from nanoscale to mesoscale and opens up a promising avenue toward ultrahigh performance osmotic power.