Nanofluidic ion regulation membranes based on two-dimensional vacancy-containing CdPS3 membrane

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 12; no. 6; pp. 3331 - 3339
• Main Authors: Zhang, Meng, Huang, Chenhui, Zhai, Zhaofeng, Kang, Xiaomin, Jiang, Ju, Qian, Xitang
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 06.02.2024
• Subjects: Cations; Conductivity; Controllability; Electric potential; Energy conversion; Fluidics; Ion transport; Ions; Membrane separation; Membranes; Nanochannels; Nanofluids; Potassium; Potassium channels (voltage-gated); Saline solutions; Separation; Sodium channels (voltage-gated); Surface charge; Transport phenomena; Transport properties; Two dimensional materials; Voltage
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta06218j

Nanofluidic ion regulation membranes have emerged as versatile platforms for applications in molecular/ion separation and energy conversion. The use of two-dimensional (2D) material-based membranes holds great potential for the regulation of nanofluidic ions owing to their unique properties of surface charges, nanochannels, and nanocapillary force. Herein, a class of 2D flexible ion-conductive membranes with surface charge-controllable and voltage-tunable ion transport properties, which are assembled with monolayered Cd vacancy-containing CdPS3 (vc-CdPS3)-based nanosheets, is reported. Importantly, the ion conductivity of the vc-CdPS3 membrane is several orders of magnitude higher than that of bulk salt solutions up to 0.1 M and reaches a plateau of ∼10 mS cm−1 in low concentrated solution (≤1 mM), demonstrating typical charge-controllable nanofluidic ion transport behavior. This membrane exhibits excellent stability and maintains an ion conductivity of 23 and 20 mS cm−1 under harsh acidic and alkaline conditions, respectively. By applying positive/negative gating voltage, ion transportation within the vc-CdPS3 membrane is tuned, resulting in low/high ion conductivity. The voltage-tunable behavior across a broad spectrum of cations with varying sizes and charges is observed, showcasing the ion-specific switch ratios of 12 and 10 for potassium and sodium ions, respectively, under an applied voltage of 2 V/−2 V. This work demonstrates the potential of vacancy-containing membranes for a variety of membrane separation applications and offer a strategy for preparing efficient ion transport devices.