Bao Zhiwei, Hou Chuangming, Shen Zhonghui, Sun Haoyang, Zhang Genqiang, Luo Zhen, Dai Zhizhan, Wang Chengming, Chen Xiaowei, Li Liangbin, Yin Yuewei, Shen Yang, Li Xiaoguang
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics and CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, 230026, P. R. China.
School of Materials Science and Engineering, State Key Lab of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, P. R. China.
Adv Mater. 2020 Jun;32(25):e1907227. doi: 10.1002/adma.201907227. Epub 2020 May 13.
Polymer-based dielectric materials play a key role in advanced electronic devices and electric power systems. Although extensive research has been devoted to improve their energy-storage performances, it is a great challenge to increase the breakdown strength of polymer nanocomposites in terms of achieving high energy density and good reliability under high voltages. Here, a general strategy is proposed to significantly improve their breakdown strength and energy storage by adding negatively charged Ca Nb O nanosheets. A dramatically enhanced breakdown strength (792 MV m ) and the highest energy density (36.2 J cm ) among all flexible polymer-based dielectrics are observed in poly(vinylidene fluoride)-based nanocomposite capacitors. The strategy generalizability is verified by the similar substantial enhancements of breakdown strength and energy density in polystyrene-based nanocomposites. Phase-field simulations demonstrate that the further enhanced breakdown strength is ascribed to the local electric field, produced by the negatively charged Ca Nb O nanosheets sandwiched with the positively charged polyethyleneimine, which suppresses the secondary impact-ionized electrons and blocks the breakdown path in nanocomposites. The results demonstrate a new horizon of high-energy-density flexible capacitors.
聚合物基介电材料在先进电子设备和电力系统中起着关键作用。尽管人们已经进行了广泛的研究来提高它们的储能性能，但在高电压下实现高能量密度和良好可靠性的同时提高聚合物纳米复合材料的击穿强度仍是一个巨大的挑战。在此，提出了一种通用策略，通过添加带负电荷的Ca Nb O纳米片来显著提高其击穿强度和储能。在聚偏二氟乙烯基纳米复合电容器中观察到了所有柔性聚合物基电介质中显著提高的击穿强度（792 MV m）和最高能量密度（36.2 J cm）。通过聚苯乙烯基纳米复合材料中击穿强度和能量密度的类似显著提高，验证了该策略的通用性。相场模拟表明，击穿强度的进一步提高归因于夹在带正电荷的聚乙烯亚胺之间的带负电荷的Ca Nb O纳米片产生的局部电场，该电场抑制了二次碰撞电离电子并阻断了纳米复合材料中的击穿路径。这些结果展示了高能量密度柔性电容器的新前景。
