AgNWs@BNNS heterostructure-enabled cellulose nanofiber composites with superior thermal conductivities and electrothermal response

Thermally conductive fillers with heterogeneous structures can integrate the advantages of their constituent components to form continuous thermally conductive pathways within composites, thereby significantly improving their thermal conduction efficiency. In this study, “point-line” heterostructured silver nanowire@boron nitride nanosheet (AgNWs@BNNS) thermally conductive fillers were synthesized via surface functionalization. Subsequently, AgNWs@BNNS were incorporated into the matrix of cellulose nanofibers (CNF), and nacre-mimetic AgNWs@BNNS/CNF thermally conductive composites were prepared using vacuum-assisted filtration followed by hot-pressing. At an optimal mass ratio of AgNWs to BNNS of 1:1 and an AgNWs@BNNS mass fraction of 80 wt%, the in-plane thermal conductivity ( λ ∥ ) of the AgNWs@BNNS/CNF composite reached 5.55 W/(m·K), representing an increase of 386.84% relative to pure CNF. Furthermore, the composite exhibited multifunctional properties, including excellent temperature-voltage response (Joule-heating temperature of 134.5 °C at 2 V with a rapid response time of 10 s), superior thermal stability (temperature at maximum weight loss rate (T dmax ) of 311.63 °C), and robust mechanical performance (tensile strength of 20.80 MPa and tensile modulus of 1.17 GPa). The thermally conductive composites developed in this work provide a viable strategy for the design of efficient thermal management materials, shedding light on potential applications in thermal management for 5G electronic devices and next generation data computing network.