LAUSR

As the rapid development of intelligent systems moves toward flexible electronics, capacitors with extraordinary flexibility and an outstanding energy storage performance will open up broad prospects for powering portable/wearable electronics and pulsed power applications. This work presents a simple one‐step process to fabricate a flexible Mn‐doped 0.97(0.93Na0.5Bi0.5TiO3‐0.07BaTiO3)‐0.03BiFeO3 (Mn:NBT‐BT‐BFO) inorganic thin film capacitor with the assistance of a 2D fluorophlogopite mica substrate. The film element, which has a high breakdown strength, great relaxor dispersion, and the coexistence of ferroelectric and antiferroelectric phases, has a high recoverable energy storage density (Wrec ≈81.9 J cm−3), high efficiency (η ≈64.4%), superior frequency stability (500 Hz–20 kHz), excellent antifatigue property (1 × 109 cycles), and a broad operating temperature window (25–200 °C). The all‐inorganic Mn:NBT‐BT‐BFO/Pt/mica capacitor has a prominent mechanical‐bending resistance without obvious deterioration in its corresponding energy storage capability when it is subjected to a bending radius of 2 mm or repeated bending for 103 cycles. This work is the first demonstration of an all‐inorganic flexible film capacitor and sheds light on dielectric energy storage devices for portable/wearable applications.