High-performance energy storage in tungsten bronze-based ferroelectric ceramics under low electric field

The utilization of a high entropy approach for the design of high-performance perovskite dielectric capacitors has been gaining much attention for the development of next-generation pulse power capacitors. This work develops a novel lead-free relaxor ferroelectric ceramic Gd_0.03Ba_0.47Sr_0.485–1.5xBi_xNbO₆ via Bi-doped in tungsten bronze structures, achieving breakthrough low-electric-field energy storage performance with a high recoverable energy density (W_rec = 2.57 J/cm³) and efficiency (η = 81.54 %) at 215 kV/cm—superior to most reported lead-free tungsten bronze-structured (TTB) (W_rec/E = 0.012 J cm⁻² kV⁻¹). The enhanced properties originate from Bi³⁺-induced oxygen vacancy suppression and lattice distortion γ = 1.72), coupled with grain refinement (2.25 μm) that homogenizes electric fields. Remarkably, the material demonstrates exceptional stability under harsh conditions. Our work establishes a feasible paradigm for high-efficiency dielectric capacitors operable at low fields, showing significant potential for pulse power systems and miniaturized electronics.