Carbon-doped inorganic nanoassemblies as fillers to tailor the dielectric and energy storage properties in polymer-based nanocomposites

Polymer-based nanocomposites are excellent and promising in developing dielectric and energy storage applications, and one-dimensional (1D) nanofibers with large aspect ratio exhibit superiority in improving dispersibility, dielectric properties and energy storage performance of polymer nanocomposites as compared with their spherical counterparts. In this work, novel heterostructural carbon-doped inorganic nanoassemblies (TiO2/C nanofibers, NFs) were designed and synthesized in site via easy-processing electrospinning technique. Three different carbon contents of TiO2/C NFs were obtained as 2 wt%, 4.5 wt% and 13.6 wt% by regulating precalcination conditions, respectively. P(VDF-HFP) was chosen to incorporate with different nanofibers as prepared due to its relatively high dielectric constant. A comparative study on dielectric energy storage performance of the TiO2/C NFs/P(VDF-HFP) nanocomposites has been systematically presented. The results reveal that the dielectric constant and the energy density are significantly enhanced for nanocomposites with appropriate content of doped carbon inside NFs. At relatively low doping content, the carbon nanoparticles could well disperse in TiO2/C NFs for forming numerous micro-capacitors, which is beneficial for enhancing interfacial polarization and suppressing loss. This work provides insights into the effect of the carbon-doped nanoassemblies for further improving energy storage capability of polymer nanocomposites for high-performance device applications. [Display omitted] •High-aspect-ratio heterostructural TiO2/C nanofibers were prepared in situ via electrospinning.•Numerous microcapacitors were formed within TiO2/C nanofibers for the well-dispersed carbon nanoparticles.•Dielectric properties of TiO2/C nanofibers/P(VDF-HFP) nanocomposites were improved.•The best energy storage density of P(VDF-HFP) nanocomposites could be achieved with small content of TiO2/C nanofibers.