| Autor: |
Cao M; Lab of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310058, China., Li L; Lab of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310058, China., Guo RZ; Lab of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310058, China., Wu SY; Lab of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310058, China., Chen XM; Lab of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310058, China. |
| Abstrakt: |
Metal-polymer dielectric composites show promising potential as embedded capacitors, whereas it remains a great challenge to achieve a high dielectric constant (ε r ) and low dielectric loss (tan δ) simultaneously. This work demonstrates a strategy for overcoming this challenge. Al nanoparticles with self-passivated ultrathin Al 2 O 3 shells are compacted under the uniaxial pressure ( P ), and Al-epoxy composites are prepared by curing the liquid epoxy monomer that infiltrates into Al compacts. The contacting regions between adjacent Al nanoparticles are flattened and enlarged during the compacting process, so that the ultrathin Al 2 O 3 parallel-plate microcapacitors are constructed by the insulating Al 2 O 3 shells and conductive Al cores. The composite with P of 100 MPa and Al volume fraction (υ Al ) of 53.7% exhibits the ε r of 189 at 10 kHz, which is much higher than the ε r (48-102) of 0-3 type Al-polymer composites with similar υ Al and even higher than the highest ε r (160) reported in the Al-polymer composite with υ Al > 80%. Furthermore, the present composites show low tan δ (<0.03) and good frequency and temperature stability of ε r . The finite element simulation proves that the construction and enlargement of ultrathin Al 2 O 3 parallel-plate microcapacitors dramatically increase the electric energy stored in Al 2 O 3 and therefore greatly improve the ε r . |
