Dual-Band Electrochromic Optical Modulation Improved by a Precise Control of Lithium Content in Li₄₊Ti₅O₁₂

Area of Science:

• Materials Science
• Energy Science

Background:

• Dual-band electrochromic smart windows offer energy efficiency by controlling solar irradiation and visible light.
• Current limitations in materials and preparation hinder practical application of dual-band electrochromic technology.

Purpose of the Study:

• To develop a novel electrochromic material for dual-band optical modulation.
• To investigate the potential of Li$_{4}$Ti$_{5}$O$_{12}$ for independent visible and near-infrared light control in smart windows.

Main Methods:

• Synthesized Li$_{4}$Ti$_{5}$O$_{12}$ electrochromic material with controlled lithium content.
• Fabricated a prototype smart window device utilizing the developed material.
• Evaluated optical transmittance and thermal modulation performance in visible and near-infrared regions.

Main Results:

• Achieved dual-band optical modulation with Li$_{4}$Ti$_{5}$O$_{12}$, enabling distinct bright, cool, and dark modes.
• Demonstrated over 60% transmittance contrast in both visible and near-infrared spectra.
• Attained significant apparent temperature adjustments of 7 °C and validated performance in a house model.

Conclusions:

• Li$_{4}$Ti$_{5}$O$_{12}$ presents a promising new material system for dual-band electrochromic smart windows.
• Precise control of lithium content is crucial for optimizing dual-band modulation.
• The developed technology shows potential for energy-saving applications in buildings.