Field-dependent nonlinear electrical response characteristics in polymer dielectrics with sodium alginate scaffold

Polymer-based self-adaptive dielectrics are considered promising materials to meet the growing insulation needs of flexible electronic devices and high-voltage DC cables. However, the temperature-sensitive electrical performance and poor thermal management ability of polymer dielectrics are bottlenecks that limit their further development. Here, we report a novel three-dimensional microstructure, i.e., nonlinear silicon carbide (SiC) micromaterials loaded on sodium alginate (SA) aerogel, exhibiting satisfactory non-linear electric conductivity with ultra-high thermal conductivity (3.86 W m-1 K-1, compared to 0.21 W m-1 K-1 of the pure epoxy resin). The SA aerogel, rich in high-density pores, is conductive to SiC forming a highly interconnected network structure under low loading, which endows polymer composites with the ability to quickly disperse charges under high electric field. In addition, the three-dimensional interconnected SiC network can disperse the Joule heat from local currents generated by nonlinear behavior, preventing thermal breakdown caused by the adverse effect of heat accumulation on the electrical properties of the material. In combining the advantages of nonlinear electrical conductivity characteristics, high thermal management ability, and low load capacity, this strategy expands the application scenarios of electric field self-adaptive polymer materials under high-temperature conditions.Graphical abstractWe report a novel three-dimensional microstructure dielectric composite with self-assembly SiC on sodium alginate aerogel. Due to the high interconnectivity and porous structure of SA aerogel, efficient construction of conducting paths is achieved at a low filler content (1 vol%), which endows the composite with satisfying nonlinear conductivity and thermal management capacity.