Oppositely charged aligned bacterial cellulose biofilm with nanofluidic channels for osmotic energy harvesting

The reverse electrodialysis (RED) is one of the most promising approaches for osmotic energy harvesting. Recently, the RED devices based on nanofluidic channels are considered as the high-performance osmotic energy generators. However, the high cost and the difficult processing of these materials used in RED devices restrict their development in the field. Here, we first report the osmotic energy harvesting device based on negatively and positively charged aligned bacterial cellulose (N-ABC, and P-ABC) membranes. The high surfaced charge density and narrow nanochannel can promote the ion selectivity and transmissibility. By controlling the mixing of artificial sea water (0.5 M) and river water (0.01 M), an output power density of 0.23 W m−2 can be obtained, which is the highest value of the nanocellulose based materials. By connecting 18 units of BC-RED device, the output voltage can reach up to 2.34 V, which can directly power the LED. This research paves the way for application of BC membranes as ion-exchange membranes in RED devices for the osmotic energy harvesting and opens up a new way to use the nanochannels in BC nanofibers.