High-efficiency energy storage in Cr-modified BiFeO3 thin films with suppressed leakage current and improved ferroelectricity
摘要
In ferroelectric thin-film-based energy storage technology, achieving high energy storage density and excellent fatigue endurance are essential. Transition metal doping has been widely adopted to enhance crystallinity and suppress oxygen vacancy formation, thereby improving both energy storage performance and long-term reliability. In this study, the influence of Cr doping on the energy storage and ferroelectric properties of BiFeO3 (BFO) thin films was systematically examined. Cr-doped BFO thin films with varying Cr concentrations (0, 2, 4, 6, and 8 mol%) were fabricated on (200) Pt/TiO2/SiO2/Si substrates, and they exhibited a preferential c-axis orientation. Enhanced crystallinity, reduced leakage current, and improved ferroelectric behavior were observed at a Cr concentration of 4 mol%, whereas further doping led to deterioration in these properties. Notably, the 4 mol% Cr-doped BFO thin film achieved the highest recoverable energy density of approximately 79.3 J/cm3 and an energy storage efficiency of about 74.2%. Furthermore, this optimally doped film demonstrated excellent fatigue endurance up to 1010 charge–discharge cycles.