Enhanced energy density of PVDF-based nanocomposites via a core–shell strategy
Jingjing Xu, Chao Fu, Huiying Chu, Xianyou Wu, Zhongyang Tan, Jing Qian, Weiyan Li, Zhongqian Song, Xianghai Ran, Wei Nie
Abstract
Abstract In recent years, high energy density polymer capacitors have attracted a lot of scientific interest due to their potential applications in advanced power systems and electronic devices. Here, core–shell structured TiO 2 @SrTiO 3 @polydamine nanowires (TiO 2 @SrTiO 3 @PDA NWs) were synthesized via a combination of surface conversion reaction and in-situ polymerization method, and then incorporated into the poly(vinylidene fluoride) (PVDF) matrix. Our results showed that a small amount of TiO 2 @SrTiO 3 @PDA NWs can simultaneously enhance the breakdown strength and electric displacement of nanocomposite (NC) films, resulting in improved energy storage capability. The 5 wt% TiO 2 @SrTiO 3 @PDA NWs/PVDF NC demonstrates 1.72 times higher maximum discharge energy density compared to pristine PVDF (10.34 J/cm 3 at 198 MV/m vs. 6.01 J/cm 3 at 170 MV/m). In addition, the NC with 5 wt% TiO 2 @SrTiO 3 @PDA NWs also demonstrates an excellent charge–discharge efficiency (69% at 198 MV/m). Enhanced energy storage performance is due to hierarchical interfacial polarization among their multiple interfaces, the large aspect ratio as well as surface modification of the TiO 2 @SrTiO 3 NWs. The results of this study provide guidelines and a foundation for the preparation of the polymer NCs with an outstanding discharge energy density.