Highly Strong and Tough Transparent Aramid Nanofiber Aerogel Films for Passive Heating Energy‐Efficient Windows

Abstract Aerogel energy‐efficient glass can effectively reduce building energy consumption, but the low light transmission and weak mechanical properties greatly limit the application of aerogel in energy‐efficient windows. Herein, a modified aramid nanofiber aerogel with outstanding mechanical strength (1.80 MPa, pull over 30000 times its weight), transparency (94.38% in the infrared region), and resistance to extreme environments (thermal insulation, frost resistance, flame retardancy, and self‐extinguishing) is designed and synthesized using nanowire domain space structure strategy. The aerogel used for energy‐efficient windows to reduce energy consumption in buildings is demonstrated. When the aerogel energy‐efficient windows are applied in winter, the average temperature of the energy‐efficient windows during the period from 10:00 a.m. to 4:00 p.m. is 4.01 and 7.01 °C higher than the ordinary glass house and the outdoor temperature, respectively. Carbon reduction calculations show that even in the coldest provinces of China, poly(terephthaloyl chloride‐co‐phenylenediamine‐co‐2‐(4‐Aminophenyl)‐1H‐benzimidazol‐5‐amine) (PTPA) aerogel for passive heating can reduce CO 2 emissions by 94.14 Kg m −2 per year. This study provides a new strategy for synthesizing transparent aramid aerogels and a new way to develop passive heating and warming energy‐efficient windows for the next generation of energy‐efficient and environmentally friendly buildings.