Simultaneous electricity generation and steam production from a wide range of salinity by using unique nanofluidic diode

Hygroelectric generator shows the advantages of sustainability, stability and low cost, and has attracted widespread attention in recent years. However, current power generators based on hydrovoltaic effect are limited to exploiting deionized (DI) water or low ion concentrations, which severely restricts their practical applications. Herein, we report a device concept that can break the solution salinity limit to generate electricity and produce clean water vapor at the same time, which cannot be achieved by any existing hygroelectric technology. Such multifunctional generator design is based on the synergistic effect between nanofluidic diode governed ionic transport and REDOX reaction, which guarantees the sustained power generation in a wide range of ion concentrations over 8 orders of magnitude. Except for harvesting energy from a dynamically changing aqueous solution, the power output can be further augmented by introducing photo-thermal response and reducing heat loss. Under one sunlight irradiation, the device achieves a power density output of 122.21 μW cm−2 in 2 M NaCl solution. While generating electricity, the device allows solar-enabled steam generation and gives rise to an additional steam of 3.23 kg m−2 h−1. These results represent a new breakthrough in improving the operational reliability, power output and versatility of hygroelectric generators in dynamic salinity environments.