High Energy Storage Efficiency with Fatigue Resistance and Thermal Stability in Lead-Free Na0.5K0.5NbO3/BiMnO3 Solid-Solution Films

Abstract

The ferroelectric, leakage, dielectric, and energy storage properties of lead-free Na0.5K0.5NbO3/BiMnO3 (KNN/BMO) solid-solution films are investigated. The strong ferroelectric relaxation behaviors of slim ferroelectricity with small remanent polarization and coercive field induce a high energy-storage density and efficiency at room temperature. The energy density reaches 14.8 J cm−3, even the efficiency is up to 79.79% under the applied electric field of 985.66 kV cm−1. Moreover, the energy storage performances of KNN/BMO solid-solution films exhibit good thermal stability over a wide temperature range and high ferroelectric fatigue endurance after switching 106 bipole electrical cycles. KNN/BMO solid-solution films can replace lead-based films and other outstanding lead-free systems in the energy storage performance.