Mechanically Enhanced, Environmentally Stable, and Bioinspired Charge-Gradient Hydrogel Membranes for Efficient Ion...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage and Conversion

Background:

• Soft hydrogel power sources offer clean energy generation but suffer from low ion selectivity, high resistance, and concentration polarization, limiting power output.
• Existing hydrogel membranes face challenges in efficient ion transport and power generation.

Purpose of the Study:

• To design a vertically stacked hydrogel artificial electric organ inspired by the electric ray's electric organ to enhance output current.
• To improve ion transport and mitigate ion concentration polarization in hydrogel membranes.
• To explore the multifunctional applications of the developed hydrogel device.

Main Methods:

• Construction of ultrathin ion-selective hydrogel membranes with a built-in charge gradient.
• Fabrication of a vertically stacked hydrogel artificial electric organ.
• Performance characterization of the device's electrical output and sensing capabilities.
• Density functional theory (DFT) calculations to analyze ion transport mechanisms.

Main Results:

• A single hydrogel artificial electric organ achieved high outputs of approximately 290 mV and 1.46 mA cm⁻² with rechargeability.
• Charge-gradient membranes demonstrated accelerated ion transport and reduced ion concentration polarization compared to non-gradient membranes.
• DFT revealed a lower energy barrier for ion transport in charge-gradient membranes.
• The device functioned effectively as a linear self-powered pressure sensor for activity monitoring even after ion gradient dissipation.

Conclusions:

• The study highlights the critical role of ion-selective membrane structure and design in advancing artificial gel power generation.
• The developed hydrogel artificial electric organ offers a promising pathway for high-performance, flexible clean energy sources.
• The device's dual functionality as a power source and sensor opens new avenues for multifunctional material applications.