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选用金属Ni和Ag纳米颗粒作为导体相,采用共混法分别制备了击穿场强较高的Ni-BaTiO3/聚偏氟乙烯(Ni-BaTiO3/PVDF)和Ag-BaTiO3/PVDF三相复合材料。研究了导体相Ni和Ag添加量、粒径及导体种类对复合材料击穿场强的影响,发现Ni-BaTiO3/PVDF和Ag-BaTiO3/PVDF三相复合材料的击穿场强均随导体添加量的增加呈现先升高后降低的趋势,且在适宜的导体添加量下复合材料均表现出高于未添加导体相的BaTiO3/PVDF两相复合材料的击穿场强;添加同类导体Ni时,Ni粒径越小,三相复合材料的击穿场强提高越明显;导体添加量与粒径均相同时,Ni-BaTiO3/PVDF复合材料的击穿场强较高,当粒径50nm的Ni添加量为体积分数1.90%时,其击穿场强可达200kV/mm,储能密度比BaTiO3/PVDF两相复合材料提高4倍。这些结果可用库仑阻塞效应很好地解释。
Ni-BaTiO3 / PVDF and Ag-BaTiO3 / PVDF three-phase composites with high breakdown strength were prepared by using Ni and Ag nano-particles as the conductor phase. . The effects of Ni and Ag addition amount, particle size and conductor type on the breakdown field strength of the composites were investigated. The breakdown fields of the Ni-BaTiO3 / PVDF and Ag-BaTiO3 / PVDF composites were investigated. The increase of the amount of BaTiO3 / PVDF composite composites at first and then decreased with the increase of the amount of conductor, which is higher than that of the BaTiO3 / PVDF two-phase composite without addition of conductor phase. The breakdown strength of Ni-BaTiO3 / PVDF composites increases with the addition of Ni and the size of Ni-BaTiO3 / PVDF composites. When the Ni particle size is smaller, the breakdown strength of the three-phase composites increases more obviously. When the Ni content is 1.90%, the breakdown strength is up to 200kV / mm, and the energy storage density is four times higher than that of BaTiO3 / PVDF composites. These results are well explained by the Coulomb blockade effect.