Flexible Energy-Storage Ceramic Thick-Film Structures with High Flexural Fatigue Endurance

Abstract

When developing flexible electronic devices, trade-offs between desired functional properties and sufficient mechanical flexibility must often be considered. The integration of functional ceramics on flexible materials is a major challenge. However, aerosol deposition (AD), a room-temperature deposition method, has gained a reputation for its ability to combine ceramics with polymers previously considered incompatible with the conventional high-temperature sintering process. In this work, 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 (PMN–10PT) thick films were deposited directly on a polyimide substrate using the AD method. As a result, dense and flexible relaxor-ferroelectric thick films were produced by a one-step direct-integration, suitable for large-scale production. After annealing of as-deposited PMN–10PT films at 400 °C, stress-relaxation occurs, which is responsible for the development of a relaxor-ferroelectric character. Achieved high polarization (38 μC·cm–2), high dielectric breakdown strength (∼1000 kV·cm–1), and low hysteresis losses lead to improved recoverable energy density and energy-storage efficiency of the annealed thick films, reaching 10 J·cm–3 and 73% (at 1000 kV·cm–1), respectively. The thick films were subjected to flexural bending tests, which showed high flexibility (1.1% bending strain) and high durability (105 bending cycles). This stable energy-storage operation makes ceramic-polymer layered structures promising for integration into a wide range of flexible electronic devices.