Polymeric capacitors are well suited for short-term energy storage and are readily integrated with devices due to their low weight, easy shape forming properties and flexibility. Bi-axially oriented polypropylene (BOPP) is the best commercially available dielectric polymer, but it has an energy density of 2 J/cm3 - which is quite low - due its very low dielectric constant (εr ˜ 2.2). Therefore, requirements for a high-efficiency capacitive storage system have increased the need for dielectric materials with superior energy density.

To solve this long-standing problem, researchers in the organic nano-piezoelectric device laboratory group at Jadavpur University, Kolkata, India have prepared titanium dioxide (TiO2) nanoparticles (NPs) embedded in a polyvinylidene fluoride (PVDF) nanocomposite (PNC) film by a cost-effective technique that is suitable for both energy storage and conversion applications. It turns out to be an excellent material for energy storage applications due to an increased dielectric constant (εr ˜ 32 at 1 kHz) and high breakdown strength (400 MV/m). It exhibits the high energy density of 4 J/cm3, which is 2 times higher than BOPP. Thus it can be tailored for a variety of commercial applications such as hybrid electric vehicles, medical devices and electrical weapon systems. Our device may fulfil the ever increasing demand for efficient, reliable and environmentally friendly lead-free energy storage devices for use in power electronics and high-power delivery systems.

Owing to the electroactive nature and extraordinary mechanical properties of the nanocomposite, the material also has great potential for fabricating piezoelectric nanogenerators (PNGs) which have recently attracted much attention in the area of mechanical energy harvesting for self-powered devices. The feasibility of piezoelectric voltage generation from a PNG is demonstrated under periodic mechanical vibration, which is also promising for a broad range of applications such as speed determination, transportation monitoring, frequency count in industrial batch fabrication, noise detection, and acoustic sensing to name a few.