Novel core–shell-structured ironbark-like TiO2 as fillers for excellent discharged energy density of nanocomposites

Abstract

The perpendicular orientation of nanowires to electric elds would greatly improve the breakdown strengths (E b) of polymer-based nanocomposites, however, the relatively small polarization at small ller fraction, and thus the unsatisfactory discharged energy density (U d), greatly restrict their further application. In this study, x vol.% TO@TO/PVDF nanocomposites with superior energy storage performances have been fabricated, where the ironbark-like TiO 2 llers (TO@TO) with core-shell structures lead to greatly enhanced polarization and E b simultaneously. The former is due to the coupling effects of the increased interfacial polarization, the latter is due to the enhanced path tortuosity of electric tree growing at small TO@TO fraction. Strikingly, an excellent U d of 13.1 J/cm 3 was achieved in the 1.5 vol % TO@TO/PVDF nanocomposite at 383 MV/m, which is greatly increased by 220% compared with that of pure PVDF (5.98 J/cm 3). The primary results might provide a strategy to design and fabricate nanocomposites with satisfactory energy storage performances as well as the exible and easyprocessing ability at small ller fraction.

Remarkably Enhanced Energy Storage Performances in Well-Designed Core–Shell Ag@TiO2–Poly(vinylidene fluoride) Nanocomposites

“…To better understand the superior performances of energy storage of x vol % Ag@TiO 2 filled nanocomposites, the U d and E b of representative PVDF-based nanocomposites reported recently are summarized in Figure . ,,,,,,,,,,,,, As is demonstrated in Figure , in contrast to other similar reports, a better discharged energy density ( U d ∼ 16.3 J/cm 3 ) has been achieved at lower electric field (∼376 MV/m), by constructing and optimizing the filler of core–shell structured x vol % Ag@TiO 2 into PVDF-based composites. The improvement may originate from several aspects: First, both the percolation effects of Ag NPs and enhanced interfacial polarizations of bark-like TiO 2 are beneficial in improving the polarization performances of x vol % Ag@TiO 2 /PVDF nanocomposites at low filling fraction.…”

“…Multi-interface ironbark-like TiO 2 NWs were prepared according to our previous reported method . After that, 0.1 g of ironbark-like TiO 2 NWs was dissolved into 40 mL of ethylene glycol with ultrasonic treatment in a flask for 2 min, and then 0.001 g of PVP was added and stirred for 30 min to dissolve it.…”

“…Multi-interface ironbark-like TiO 2 NWs were prepared according to our previous reported method. 38 After that, 0.1 g of ironbark-like TiO 2 NWs was dissolved into 40 mL of ethylene glycol with ultrasonic treatment in a flask for 2 min, and then 0.001 g of PVP was added and stirred for 30 min to dissolve it. Meanwhile, 2 vol % of AgNO 3 (m = 0.0016 g) was dissolved into another 20 mL of ethylene glycol and stirred for 2 h. Subsequently, the flask was completely dipped in the oil bath until the temperature reached 160 °C, then the AgNO 3 solution was slowly dripped into the flask, and the solution was continuously stirred at low speed for 2 h at 160 °C.…”

“…29 Above all, in this study, the bark-like TiO 2 NWs with a core−shell structure (plicate TiO 2 coated onto the surface of TiO 2 NWs), which was reported by our previous works, are selected as the carrier of the hybrid fillers. 38,39 On this basis, various fractions of Ag NPs are decorated onto the surface of bark-like TiO 2 NWs by coprecipitation method to obtain the final hybrid filler of Ag@TiO 2 NWs. The experiment and simulation results demonstrate that the hybrid Ag@TiO 2 NWs could be beneficial in improving the dielectric and energy storage performances of x vol % Ag@TiO 2 /PVDF (where x characterizes the volume fraction of Ag NPs) nanocomposites.…”