Liquid metal interface mechanochemistry disentangles energy density and biaxial stretchability tradeoff in composite capacitor film.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39242564.
- Also identified by DOI 10.1038/s41467-024-52234-4 and PMC identifier 11379682.
- Licence recorded as CC BY-NC-ND.
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Abstract
Dielectric polymer composites for film capacitors have advanced significantly in recent decades, yet their practical implementation in industrial-scale, thin-film processing faces challenges, particularly due to limited biaxial stretchability. Here, we introduce a mechanochemical solution that applies liquid metal onto rigid dielectric fillers (e.g. boron nitride), dramatically transforming polymer-filler interface characteristics. This approach significantly reduces modulus mismatch and stress concentration at the interface region, enabling polypropylene composites to achieve biaxial stretching ratio up to 450 × 450%. Furthermore, liquid metal integration enhances boron nitride's dielectric polarization while maintaining inherent insulation, producing high-dielectric-constant, low-loss films. These films, only microns thick yet quasi square meters in area, achieve a 55% increase in energy density over commercial biaxially-oriented polypropylene (from 2.9 to 4.5 J cm<sup>-3</sup> at 550 MV/m), keeping 90% discharge efficiency. Coupled with improved thermal conductivity, durability, and device capacitance, this distinctive interface engineering approach makes these composites promising for high-performance film capacitors.