Evolution-Driven Bio-Composite Aerogels for Self-Adaptive Thermal Regulation and Energy Storage.

Abstract

Nature achieves remarkable multifunctionality by integrating chemically dissimilar phases into hierarchically organized architectures. Inspired by this principle, we develop a simple and universal strategy to construct bio-composite aerogels by incorporating trivalent metal chlorides (MCl₃) into biopolymer chitosan (CTS) matrices. Coordination-driven assembly in aqueous media enables the direct formation of metal ion-coordinated chitosan (CTS-M) aerogels without external acids or additional crosslinkers. These aerogels exhibit reversible brittle-to-flexible transitions under humidity stimuli, together with exceptional mechanical resilience, enabling self-adaptive thermal insulation under temperature extremes. Upon pyrolysis, the same precursor is converted into conductive carbon-metal oxide (C-M₂O₃) aerogels, where metal oxide nanocrystals are embedded within an interconnected carbon framework. This structural integration couples a continuous electron-transport network with redox-active domains, thereby promoting charge-transfer and increasing accessible storage sites. As a representative example, the C-V₂O₃ cathode for aqueous zinc-ion batteries (ZIBs) delivers excellent energy-power performance (656 Wh kg^-1 at 200 W kg^-1, 178 Wh kg^-1 at ∼20 000 W kg^-1) with 85% capacity retention after 10 000 cycles, outperforming previously reported carbon-metal oxide systems. By linking adaptive thermal regulation and electrochemical energy storage through a single precursor-to-function pathway, this work establishes an evolution-driven aerogel design paradigm for next-generation multifunctional materials.