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随着功率型电子器件设备向小型化和高性能化方向发展, 迫切需要高储能密度、高充放电效率、易加工成型、性能稳定的介质材料. 目前BaTiO 3基介电陶瓷具有较高的介电常数, 但耐击穿场强低、柔性差, 而聚合物基电介质材料具有超高功能密度、超快的充放电响应时间、良好的柔韧性、高耐击穿场强、质量轻等优点, 但聚合物材料本身存在介电常数较低、极化强度低等问题, 因此导致两者储能密度较低, 限制了在小型化功率型电容器元件中的应用. 为了获得高储能性能材料, 科学家提出通过复合的方式将高介电常数无机陶瓷填料加入到聚合物中, 提高材料的储能性能, 界面在材料的性能中扮演着至关重要的角色, 本文综述了钛酸钡基/聚偏氟乙烯复合电介质材料界面设计和控制的最新研究进展. 总结了偶联剂、表面活性剂表面改性、聚合物壳层表面修饰、无机壳层表面改性、有机-无机壳层协同改性等界面改性方法对复合材料极化和储能性能的影响, 探讨了现有的界面模型与理论研究方法, 概述了存在的挑战和实际局限性, 展望了未来的研究方向.With the development of power electronic device equipment towards miniaturization and high performance, the dielectric materials with high energy storage density, high charge and discharge efficiency, easy processing and molding, and stable performance are urgently needed. At present, Barium titanate-based dielectric ceramics have a high dielectric constant, but low breakdown field strength and poor flexibility. Polymer-based dielectric materials have ultra-high functional density, ultra-fast charge and discharge response time, good flexibility, high breakdown field strength, light weight and other advantages, but low dielectric constant and low polarization strength. Their energy storage density is low, which limits the power capacitor component size and application scope. In order to obtain material with high energy storage performance, it was proposed to add high dielectric constant inorganic ceramic fillers to the polymer through a composite method to improve the energy storage performance of the material. The interface plays a vital role in the performance of the composite material. In this article, we review the latest research advance in the interface design and control of barium titanate/polyvinylidene fluoride composite dielectric materials. The effects of interface modification methods such as organic surface modification, inorganic functionalization and organic-inorganic synergistic modification on the polarization and energy storage performance of composite materials are summarized. The existing interface models and theoretical research methods are discussed, and the existing challenges and practical limitations, and the future research directions are prospected.
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薄膜材料 1 kHz介电常数 最高使用温度/℃ 击穿电压/kV·m–1 损耗/% 储能密度/J·cm–3 聚丙烯 (PP) 2.2 105 6400 < 0.02 1—1.2 聚酯 (PET) 3.3 125 5700 < 0.50 1—1.5 聚碳酸酯 (PC) 2.8 125 5280 < 0.15 0.5—1 聚乙烯 (PEN) 3.2 125 5500 < 0.15 1—1.5 聚苯硫醚 (PPS) 3.0 200 5500 < 0.03 1—1.5 聚偏氟乙烯 (PVDF) 12 125 5900 < 1.80 2.4 理论名称 渗流理论 Lichtenecher模型 Bruggeman模型 Maxwell-Garnett模型 公式 $\begin{array}{l} {\sigma _{\rm{c}}} \propto {(f - {f_{\rm{c}}})^t} \\ {\sigma _{\rm{c}}} \propto {({f_{\rm{c}}} - f)^{ - q}} \\ \end{array} $ $\varepsilon _{_{{\rm{eff}}}}^{^n} = {f_1}\varepsilon _1^n + {f_2}\varepsilon _2^n$ $f\dfrac{ { {\varepsilon _1} \!-\! {\varepsilon _{ {\rm{eff} } } } } }{ {2{\varepsilon _{ {\rm{eff} } } } \!+\! 2{\varepsilon _1} } } \!+\! (1 \!-\! f)\dfrac{ { {\varepsilon _2} \!-\! {\varepsilon _{ {\rm{eff} } } } } }{ { {\varepsilon _{ {\rm{eff} } } } \!+\! 2{\varepsilon _2} } } \!=\! 0$ $\dfrac{ { {\varepsilon _{ {\rm{eff} } } } - {\varepsilon _1} } }{ { {\varepsilon _{ {\rm{eff} } } } + 2{\varepsilon _1} } } = f\dfrac{ { {\varepsilon _1} - {\varepsilon _2} } }{ { {\varepsilon _1} + 2{\varepsilon _2} } }$ 字母的
含义${f_{\rm{c}}}$表示渗流阈值,
${\sigma _{\rm{c}}}$为电导率,t和q分
别为临界参数${\varepsilon _{{\rm{eff}}}}$为复合材料的介电常数,
${\varepsilon _1}$为基相的介电常数,
${\varepsilon _2}$为分散相的介电常数,
${f_2}$为填料的体积分数,
n= 1, –1, 0${\varepsilon _{{\rm{eff}}}}$为复合材料的介电常数,
${\varepsilon _1}$, ${\varepsilon _2}$分别为填料和基体的介
电常数, $f$为填料的体积分数${\varepsilon _{{\rm{eff}}}}$为复合材料的介电常数,
${\varepsilon _1}$, ${\varepsilon _2}$分别为填料和基体的介
电常数, $f$为填料的体积分数适用条件 将体系的微观结构与
宏观性能联系起来可以判断两材料复合并
联或者串联模型可以成功解释复合材料由
绝缘体向导体的转变可以模拟两种绝缘体构成
的复合材料的介电常数不足之处 影响渗流值的因素众多,
如填料的尺寸、形貌等填料含量较高时, 利用此模型
与测量值有明显的差距.仅当填料浓度小于渗
流阈值时公式才成立没有考虑到填料相的电阻率,
预测的介电常数值比实际值大 -
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