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Title: Dielectric performance of high permitivity nanocomposites: impact of polystyrene grafting on BaTiO 3 and TiO 2

Polymer nanocomposites are a promising concept to improve energy storage density of capacitors, but realizing their hypothetical gains has proved challenging. The introduction of high permittivity fillers often leads to reduction in breakdown strength due to field exclusion, which intensifies the applied electric field within the polymer matrix near nanoparticle interfaces. This has prompted research in developing new nanoparticle functionalization chemistries and processing concepts to maximize particle separation. Herein, we compare the dielectric performance of blended nanocomposites to matrix free assemblies of hairy (polymer-grafted) nanoparticles (HNPs) that exhibit comparable overall morphology. The dielectric breakdown strength of polystyrene-grafted BaTiO3 (PS@BaTiO3) systems was over 40% greater than a blended nanocomposite with similar loading (~25% v/v BaTiO3). Hairy nanoparticles with TiO2 cores followed similar trends in breakdown strength as a function of inorganic loading up to 40% v/v. Dielectric loss for PS@BaTiO3 HNPs was 2-5 times lower than analogous blended films for a wide frequency spectrum (1 Hz to 100 kHz). For BaTiO3 content above 7% v/v, grafting the polymer chains to the nanoparticle significantly improved energy storage density and efficiency, likely due to the polymer canopy mitigating interfacial transport and restricting particle-particle hot-spots by establishing a finite minimum particle separation.
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [1] ;  [1]
  1. Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States)
  2. Univ. of Southern California, Los Angeles, CA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 2; Journal Issue: 3; Journal ID: ISSN 2055-0324
Taylor & Francis
Research Org:
Univ. of Southern California, Los Angeles, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Contributing Orgs:
Air Force Research Laboratory, Materials and Manufacturing Directorate
Country of Publication:
United States
25 ENERGY STORAGE; 36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; polymer nanocomposites; hairy nanoparticles; dielectric breakdown; barium titanate; titanium dioxide
OSTI Identifier: