TEMPO-Oxidized Bacterial Cellulose Nanofibers/Graphene Oxide Fibers for Osmotic Energy Conversion

Abstract

The large osmotic energy between river water and seawater is an inexhaustible blue energy source; however, the complicated manufacturing methods used for ion-exchange devices hinder the development of reverse electrodialysis (RED). Here, we use a wet-spinning method to continuously spin meter-scale 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized bacterial cellulose (TOBC) nanofiber filaments, which are then used to construct nanochannels for osmotic energy conversion. These are then used to build a nacre-like structure by adding graphene oxide (GO), which provides narrow nanochannels in one-dimensional and two-dimensional nanofluid systems for rapid ion transport. With a 50-fold concentration gradient, the nanochannels in the fibers generate electricity of 0.35 W m −2 , with an ionic mobility of 0.94 and an energy conversion efficiency of 38%. The assembly of GO and TOBC results in a high power density of 0.53 W m −2 using artificial seawater and river water. The RED device fabricated from TOBC/GO fibers maintains a stable power density for 15 days. This research proposes a simple method to reduce the size of nanochannels to improve the ionic conductivity, ionic selectivity, and power density of cellulose-based nanofibers to increase the possibility of their application for the conversion of osmotic energy to electrical energy.

Engineered Cellulose Nanofiber Membranes with Ultrathin Low-Dimensional Carbon Material Layers for Photothermal-Enhanced Osmotic Energy Conversion

“…Cellulose nanofibers (CNFs), as a natural nanomaterial with massive reserves and low cost, have been widely used in various fields, including energy conversion, energy storage, water desalination, and biomedicine. − Because of their nanoscale dimensions, abundant chemical groups on the surface, excellent mechanical strength, and low thermal expansion coefficient, CNFs have been employed to fabricate nanofluidic membranes for osmotic energy conversion through hydrogen bonds, Van der Waals forces, and electrostatic forces between the groups. ,,− For example, oppositely charged aligned bacterial cellulose membranes have achieved 0.23 W/m 2 in osmotic energy harvesting . The external field has been introduced to facilitate the CNF-based membrane for enhancing osmotic energy conversion.…”

Robust and Highly Sensitive Cellulose Nanofiber-Based Humidity Actuators

“…Cellulose nanofibers (CNFs), as a natural biological material, have been considered as a promising functional material for use in sensors, generators, energy storage devices, , electromagnetic interference shielding, and photo-/electrocatalysis fields owing to their fascinating biodegradable, biocompatible, and renewable nature and noticeable mechanical properties . In particular, the large specific surface area and abundant hydrophilic functional groups on the surface favored for the strong interfacial interaction with other materials, making them become an ideal candidate for smart actuators.…”

A sulfonated ultramicroporous membrane with selective ion transport enables osmotic energy extraction from multiform salt solutions with exceptional efficiency

“…S10c and Table S1, ESI †). Even for some most recently reported sub-nanochannel membranes including metal-organic frameworks 24 and graphene oxide, [26][27][28][29][30][31] the energy conversion efficiency is still lower than our membrane, due to the undesired lower ion selectivity. We also simulate the concentration profile of other saline solutions, including brackish water, desalination brines, mining wastewater, and Salt Lake water.…”

“…[22][23][24] The most prominent example in nature is an electric eel, which can convert ionic gradients into high-voltage electricity of up to 600 V with the ''sub-nanoscale'' protein ion channels. 25 Studies on artificial membranes with sub-nanometer sized channels have flourished most recently and those membrane materials include metal-organic frameworks, 24 graphene oxide, [26][27][28][29][30][31] Ti 3 C 2 T x MXenes, [32][33][34] and others. [35][36][37] Until now, the highest energy conversion efficiency achieved under a 50-fold NaCl gradient has been 45.6% using a MXene membrane, while the power output has been limited to 0.53 W m À2 .…”