掺杂改性PMMA/PVDF共混聚合物基复合介质的储能性能提升

Improved energy storage performance of PMMA/PVDF blend polymer matrix composites by doping modification

  • 摘要: 薄膜电容器在高压输电换流站、新能源汽车电驱动控制器、电磁武器脉冲功率电源等电气工程和电子器件领域具有重要应用。当前薄膜电容器正向着高能量密度、耐电压、耐高温等技术方向发展,对电容薄膜的电气性能提出了更高要求。本文选择铁电聚偏氟乙烯(PVDF)和聚甲基丙烯酸甲酯(PMMA)共混物作为储能聚合物基体,以具有高介电常数的纳米粒子BaTiO3和具有高电子亲和能的有机分子半导体6, 6-苯基C61丁酸甲酯(PCBM)作为掺杂相,综合利用BaTiO3的高介电特性及PCBM的捕获电荷能力,提高复合介质的极化强度与击穿场强,显著改善储能性能。研究表明,单掺杂BaTiO3时,掺杂含量为3wt%时复合介质综合性能最优;在此基础上,随着PCBM掺杂含量增大其储能密度和充放电效率提升明显。当PCBM掺杂含量为2wt%时,含有3wt%BT的PMMA/PVDF复合介质具有优异的储能性能,当电场为579.67 kV/mm时,放电能量密度达到15.60 J/cm3且充放电效率为75.30%。本文首次提出基于少量无机高介电协同有机分子半导体功能填料的聚合物薄膜储能性能改性研究,通过加入少量的BaTiO3,既避免了由于BaTiO3含量过高而导致的绝缘性能下降问题,又保证了BaTiO3粒子对复合介质介电常数和极化性能的提升。同时,为了进一步改善因低介电常数基体与高介电常数BaTiO3颗粒之间的电场畸变所导致的击穿强度下降问题,考虑在复合介质中加入一定量的PCBM,利用PCBM强大的电子亲和能力,在复合介质中构筑深陷阱以捕获和束缚载流子,抑制载流子的迁移,提升复合介质的击穿场强,从而综合提升了复合介质的储能性能,这为开发储能性能优异的聚合物复合介质提供了一种新思路。

     

    Abstract: Thin film capacitors have important applications in the fields of electrical engineering and electronic devices such as high voltage transmission converter stations, new energy vehicle electric drive controllers, electromagnetic weapon pulse power supply and so on. At present, thin-film capacitors are developing towards the technical direction of high energy density, voltage resistance, high temperature resistance and so on, which put forward higher requirements for the electrical performance of capacitor films. In this study, ferroelectric polyvinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA) blends were selected as the energy storage polymer matrix, and BaTiO3 nanoparticles with high dielectric constant and organic molecular semiconductor 6, 6-phenyl C61 methyl butyrate (PCBM) with high electron affinity were used as the doping phase. The high dielectric properties of BaTiO3 and the ability of PCBM to capture charge are comprehensively utilized to improve the polarization strength and breakdown field strength of the composite medium and significantly improve the energy storage performance. The results show that when the doping content is 3wt%, the composite media has the best comprehensive performance. On this basis, with the increase of PCBM doping content, its energy storage density and charge-discharge efficiency improved significantly. When PCBM doping content is 2wt%, PMMA/PVDF composite medium containing 3wt% BaTiO3 has excellent energy storage performance. When the electric field is 579.67 kV/mm, the discharge energy density reaches 15.60 J/cm3 and the charge-discharge efficiency is 75.30%. First proposed in this paper, based on a small amount of inorganic high dielectric organic molecules together semiconductor filler modified polymer film energy storage performance of the function, by adding a small amount of BaTiO3 particles, avoids insulation performance degradation caused by the high content of BaTiO3, and ensures the BaTiO3 particle on the properties of composite dielectric permittivity and polarization. At the same time, in order to further improve due to the low dielectric constant substrate with high dielectric constant BaTiO3 particles between the electric field distortion caused by the breakdown strength degradation, consider joining a certain amount of PCBM in a composite medium, use PCBM electron affinity ability, strong in composite medium build deep traps to capture and carrier, inhibit the transfer of carrier.The breakdown field strength of the composite medium is improved, so as to comprehensively improve the energy storage performance of the composite medium, which provides a new idea for the development of polymer composite medium with excellent energy storage performance.

     

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