Overview

• The fully inorganic, binder‑free electrolyte is built from exfoliated montmorillonite silicate nanosheets assembled into an approximately 2.5 µm film.
• Measured proton conductivities reached 2.3×10⁻³ S/cm at 10 °C, 6.2×10⁻³ S/cm at 100 °C, and 8.7×10⁻³ S/cm at 140 °C under 100% relative humidity.
• The membrane blocked hydrogen gas more than 100 times better than Nafion in the researchers’ tests.
• In a hydrogen fuel cell, the material delivered 1080 mA/cm² peak current density and 264 mW/cm² power at 90 °C, with stable operation from −10 °C to 140 °C.
• The work, led by Kazuto Hatakeyama and Shintaro Ida and published in Journal of Materials Chemistry A, suggests potential cost and environmental benefits from clay feedstocks while highlighting needs in large‑area fabrication, interface optimization, and long‑term validation.