One-step microbial cultivated bacterial cellulose membrane with 1D/2D nanochannels for efficient osmotic energy conversion.

Osmotic energy conversion based on bio-inspired layered membranes has garnered significant interest. However, traditional biomass ion-selective membranes suffer from complex preparation, uneconomic nature, poor selectivity, and low power density. Here, we introduce scalable one-step in situ culture for nanofluidic membrane materials (GO/C-BC) composed of graphene oxide (GO), carboxymethyl cellulose sodium salt (CMC), and bacterial cellulose (BC). This preparation method effectively combines 1D and 2D nanochannels, reduces membrane resistance, and increases power density. The GO/C-BC membrane exhibits excellent cation selectivity (0.89), achieving energy conversion efficiency of 31.40 % and delivering a power density of 7.49 W m under a 500-fold concentration gradient. Stability tests under artificial seawater and river water conditions show only a 4.44 % decrease in power density after 20 d, highlighting its excellent stability and durability. Moreover, by connecting 28 power units in series, the membrane can produce a voltage output of -4 V. This scalable and environmentally friendly biomass material presents new avenues for osmotic energy conversion.