Polymer-based composites were heralded in the 1960s as a new paradigm for materials. By dispersing strong, durable, multifunctional nanomaterials in a polymer matrix, high-performance lightweight polymer nanocomposites could be developed and tailored to individual applications. However, the challenges that remain to achieve good dispersion and uniform distribution of nanomaterials pose significant obstacles to these goals. Here, we introduce an innovative nanocomposite for energy application. Using an advanced aerosol-jet printing technique, an unprecedented dispersion and distribution of the nanoparticles (NPs) are realized for polymer-based nanocomposites, with significantly low concentration of NPs, allowing for precise control of various physical properties of interest. Perfect dispersion of NPs in the solvent can be preserved in the polymer matrix as well due to the dual atomizing and printing technique. The uniformity can be finely controlled up to 10 micro-meter scale, which is the resolution of the printer. The resultant nanocomposite contributes to the enhancement of piezoelectric and ferroelectric properties of polymer materials. Correspondingly, a triboelectric nanogenerator device based on highly-uniform and well-dispersed polymer nanocomposite showed a ~ 200% increase in output power density as compared to a neat polymer-based triboelectric generator, when subjected to identical mechanical excitations.