Energy storage enhancement of sandwich-structured nanocomposites with mono/adjacent-layer design and their synergistic effect optimization

Abstract Currently, advanced electronic devices demand capacitors with superior discharge energy density ( U d ) and charge–discharge efficiency ( η ). Sandwich-structured nanocomposites have been extensively studied to significantly enhance U d through the synergistic effect of each component layer and their interfacial effects. Herein, sandwich-structured x wt.% Ni(OH) 2 BPB nanocomposites are prepared, where upper and lower high breakdown strength ( E b , B) layers are composed of 3 wt.% Ni(OH) 2 and blended PMMA/P(VDF-HFP), while middle high polarization (P) layer is composed by various weight fraction ( x wt.%) of Ni(OH) 2 and P(VDF-HFP). Interestingly, 3 wt.% Ni(OH) 2 BPB achieves improvements in U d of 22.2 J cm −3 as well as η of 81.7% at 586 MV m −1 simultaneously. Improved energy storage performances are mainly attributed to the individual B and P layer design, as well as their synergistic coupling effects in the sandwich-structured nanocomposites. The results of experiment and simulation have concurrently demonstrated Ni(OH) 2 , PMMA and the functionalized sandwiched structured design could enhance U d and descend remanent polarization and leakage current to increase η , which helps to obtain a satisfactory energy storage performance. This study offers a valid strategy for nanocomposites possessing high energy storage performances designing.