Biomass
aerogels are highly attractive candidates in various applications
due to their intrinsic merits of high strength, high porosity, biodegradability,
and renewability. However, under low-temperature harsh conditions,
biomass aerogels suffer from weakened mechanical properties, become
extremely brittle, and lose functionality. Herein, we report a multifunctional
biomass aerogel with lamella nanostructures (∼1 μm) fabricated
from cellulose nanofibers (∼200 nm) and gelatin, showing outstanding
elasticity from room temperature to ultralow temperatures (repeatedly
bent, twisted, or compressed in liquid nitrogen). The resultant aerogel
exhibits excellent organic solvent absorption, thermal infrared stealth,
and thermal insulation performance in both normal and extreme environments.
Even at dry ice temperature (−78 °C), the aerogel can
selectively and repeatedly absorb organic solvents in the same way
as room temperature with high capacities (90–177 g/g). Excellent
heat insulation and infrared stealth performances are achieved in
a wide temperature range of −196 to 80 °C. Further, this
aerogel combines with the advantages of ultralow density (∼6
mg/cm3), biodegradability, flame retardancy, and performance
stability, making it a perfect candidate for multifunctional applications
under harsh conditions. This work greatly broadens application temperature
windows of biomass aerogels and sheds light on the development of
mechanically robust biomass aerogels for various applications under
extreme conditions.