A research team led by Lei Jiang, from Technical Institute of Physics and Chemistry (TIPC) of Chinese Academy of Sciences, in collaboration with Jilin University, reported an ultrahigh performance of blue-energy nano-generator based on 3D porous Janus membrane.  

Results were published in Science Advances in an article entitled " Unique ion rectification in hypersaline environment: A high-performance and sustainable power generator system." 

Pattle pointed out that huge Gibb’s energy was lost when the sea meets the river, early in 1954. However, still now, the huge potential (30 TW all over the world) is not properly utilized for low conversion efficiency and poor power density. The past references and technical development mainly focus on the selectivity of the membrane. 

Here, the authors have designed a versatile strategy for creating a scale-up Janus three-dimensional (3D) porous membrane–based osmotic power generator system. The output power density of this membrane-based generator reaches 2.66 W/m² (mixing seawater and river water) and up to 5.10 W/m² at a 500-fold salinity gradient (i.e., flowing salt lake into river water). The uniqueness of the membrane is facile fabrication of the membrane and as-obtained high power density. The underlying mechanism is effective ion selectively and highly rectified current (one-way ionic transport) in hypersaline solution. 

The authors claim that developing single nanopore system into Janus 3D porous membrane which moves a big step for practical application, especially the membrane is with excellent stability and facile to be scale-up. This unique ionic transport properties build a model to study the fundamental ionic behavior in confined environment and further shed light on energy conversion membrane. 

The first author is Xuanbo Zhu from Jilin University; the corresponding authors are Dr. Yahong Zhou (TIPC) and Zhenhua Jiang (Jilin University).