Optimizing coupling agent for the enhanced energy storage density of BaTiO3/P(VDF − HFP)&PMMA nanocomposite films

In order to improve the energy storage performance of nanocomposite capacitors, barium titanate (BaTiO3) nanoparticles are usually surface-modified with multiple coupling agents to improve their compatibility with poly(vinylidene fluoride − hexafluoropropylene) [P(VDF − HFP)] and Polymethyl Methacrylate (PMMA) matrix. Therefore, exploring suitable coupling agent is urgent for high-performance composite films. In this work, the coupling mechanism and interfacial interactions among coupling agents, BaTiO3, and P(VDF − HFP)/PMMA are theoretically investigated. Compared with other coupling agents in this work, Tween 20 (TW20) can reinforce the Van der Waals force and chain entanglement between BaTiO3 nanoparticles and P(VDF − HFP)/PMMA due to the longer chain segments. Therefore, TW20 can enhance the dispersibility of BaTiO3 fillers and improve the compatibility between BaTiO3 and P(VDF − HFP)/PMMA. Owing to the excellent uniformity and compactness, TW20 modified BaTiO3/P(VDF − HFP)&PMMA nanocomposite films exhibit the excellent discharge energy density of 14.4 J cm−‍3 and efficiency of 77.3% at 557 kV mm−‍‍1, which is 3 times higher than that of unmodified BaTiO3/P(VDF − HFP)&PMMA nanocomposite films. This study declares that optimizing coupling agent can boost the energy storage density of nanocomposites films.