A moist-electric generator based on oxidized and aminated regenerated cellulose

Abstract

Moist-electric generation has been more focused in recent years, which is an emerging sustainable energy harvesting technology. Moist-electric generator (MEG) is a prospective energy harvesting device that collects energy only from humidity. While the existed researches focused on the ionic wood, cellulose nanofibril and cellulose acetate, this work pays attention to the oxidized regenerated cellulose (ORC) and aminated regenerated cellulose (ARC) prepared by urea/NaOH/water system from pulp, which has excellent hydrophilicity and abundant active sites attributing to the abundant functional groups and three-dimension porous structure. Its asymmetric active electrode and asymmetric ORC and ARC structure cause a humidity gradient between the two electrodes as exposed in a humidity environment, which produce potential difference under the ion concentration gradient for the directional transport of protons derived from the ionization effect, thus generating an electric current in external circuit. Of which, 12-ORC-MEG can generate an open-circuit voltage of 1.07 V at 85%RH humidity. 5-ARC-MEG can produce the output voltage as high as 4.20 V for the brought more isoelectric points by grafting amino, which is about 4 times than that of 12-ORC-MEG. The MEG as a sensor and generator can generate a certain output voltage in contact with sweaty fingers or intermittent fog. Just one 5-ARC-MEG can power micro-electronic devices, such as LED lamp and watch. This work develops a simple, inexpensive, and green MEG with renewable cellulose material that can generate sustainable moist-electric conversion from ambient humidity. It has great potential in green energy and opens up new possibilities for portable electronic products.