Osmotic energy conversion with low impedance using an ultrasmall MoS2 nanosheet composite membrane

Abstract

A 2D nanomaterial membrane exhibits promising applications for salinity gradient energy harvesting. However, low porosity and a long path in the 2D nanomaterial membrane lead to high impedance for ion transport which causes poor performance. Herein, we demonstrate a composite membrane containing ultrasmall MoS₂ nanosheets (∼100 nm) and cellulose nanofibres with a short ion transport path for osmotic energy conversion. The size effects of MoS₂ nanosheets on the performance were studied, which proved small nanosheets can improve the performance of power generation. Ultrasmall MoS₂ nanosheets in the membrane provide a short path for ion transport, decreasing the membrane's impedance. This membrane can provide a power density of 2.3 W m⁻² with a resistance of 48 kΩ at room temperature. This work demonstrates that decreasing the ion transport path in 2D nanomaterial membranes is a promising strategy to decrease the resistance of membranes for osmotic power generation.