Scalable fabrication of regenerated cellulose nanohybrid membranes integrating opposite charges and aligned nanochannels for continuous osmotic energy harvesting

• Published in: Nano energy Vol. 115; p. 108693
• Main Authors: Zhou, Binglin, Lin, Zewan, Xie, Zhijiang, Fu, Xiaotong, Yuan, Zhanhong, Jiao, Chenlu, Qin, Xingzhen, Ye, Dongdong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023
• Subjects: Cellulose; Membrane; Nanofluid; Nanostructure; Osmotic energy conversion; Membrane; Nanostructure; Osmotic energy conversion; Nanofluid; Cellulose
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2023.108693

Nanomaterials are widely used in constructing reverse electrodialysis (RED) systems with charged nanochannels for osmotic energy harvesting. However, preparing low-cost, large-scale, and high-performance RED systems with significantly improved ion selectivity, ion flux, and output power density is still a challenge. Herein, we develop a facile solution-casting method to fabricate oriented regenerated cellulose (RC)/carbon nanotubes (CNTs) nanohybrid membranes. After integrating chemical modification (i.e., TEMPO oxidation and quaternization) and structural densification, both negatively charged N-RC/N-CNTs and positively charged P-RC/P-CNTs membranes demonstrated significantly enhanced ionic conductivity in a low-concentration solution (4.02 ×10−4 and 3.59 ×10−4 S cm−1, respectively). Particularly, the P–N unit not only yields an output power density of 5.28 W m−2 in a 50-fold concentration gradient, which exceeds the commercial standard (5 W m−2), but also achieves long-term stability over 50 days. As a proof of concept, we created a RED system with 20 P–N units connected in series which successfully powered an electronic calculator with an output voltage of 2.06 V under artificial seawater and river water conditions. This work improves the development of natural renewable materials for high-performance osmotic energy conversion. [Display omitted] •Low-cost, large-scale, and high-performance regenerated cellulose membranes were fabricated.•Casting-method and chemical-modification endowed membranes with aligned nanochannels and opposite charges.•The membranes demonstrated a high output power density of 5.28 W m−2 under 50-fold concentration gradient.•The connected membranes could drive an electronic calculator.