Deep eutectic solvent-modified sulfonated silk nanofibers for hydrogel moisture electric generators in energy...

Area of Science:

• Materials Science
• Energy Harvesting
• Nanotechnology

Background:

• Ambient moisture contains significant energy, but conventional hydrogels show poor performance in moisture-enabled electricity generators (MEGs) due to inefficient ion transport.
• Silk nanofibers (SNFs) offer potential for improved hydrogel properties, but their application in MEGs requires specific functionalization and integration strategies.

Purpose of the Study:

• To develop a high-performance silk nanofiber-based hydrogel for moisture-enabled electricity generation (MEG).
• To investigate the impact of sulfonated silk nanofibers (SSNFs) on hydrogel properties and MEG performance.
• To demonstrate the scalability and practical application of the developed SSNF-based hydrogel MEG (SS-HMEG).

Main Methods:

• Sulfonated silk nanofibers (SSNFs) were synthesized using a deep eutectic solvent (DES) system.
• A polyacrylamide (PAM) hydrogel matrix was fabricated incorporating SSNFs and LiCl using a DI water/glycerol solvent system.
• The SSNF-integrated hydrogel was assembled into a moisture-enabled electricity generator (SS-HMEG) device.

Main Results:

• The SSNF-integrated hydrogel exhibited enhanced moisture absorption (66.3%) and fracture strength (+74%).
• The SS-HMEG device generated electricity spontaneously across a wide relative humidity (RH) range (45%-85%).
• At 85% RH, the device achieved an open-circuit voltage (Voc) of 1.19 V and short-circuit current (Isc) of 59.2 μA, maintaining >0.95 V at -20 °C.
• Series integration of 40 units produced 38.22 V, capable of powering a commercial humidity sensor.

Conclusions:

• The developed SSNF-based hydrogel significantly improves moisture absorption and mechanical strength, leading to enhanced MEG performance.
• The SS-HMEG demonstrates stable electricity generation over a broad RH range and low temperatures, highlighting its robustness.
• This work presents a scalable and sustainable strategy for utilizing silk nanofibers in advanced energy harvesting technologies.