Improving high‐temperature capacitive energy storage of biaxially oriented polypropylene through titanium dioxide deposition layer by atmospheric pressure plasma jets

Polymer film capacitors experience a sharp decrease in charge–discharge efficiency and energy density under high‐temperature environments, which remains an urgent issue to address. In this article, atmospheric pressure plasma jet (APPJ) is used to deposit TiO 2 to improve the energy storage performance of biaxially oriented polypropylene (BOPP) film in high‐temperature environment. The APPJ uses argon as the working gas and adopts a multielectrode grounding configuration to obtain the stable jet state. The precursor solution is prepared using tetraethyl titanate (TET) mixed with ethanol in a ratio of 5:3. The results show that the charge–discharge efficiency and discharge energy density (from 3.1 to 5.7 J cm –3 ) of BOPP films deposited by APPJ are improved at 120°C.