Ultra-fast charge-discharge and high-energy storage performance realized in K0.5Na0.5NbO3-Bi(Mn0.5Ni0.5)O-3 ceramics

Lead-free relaxor ceramics (1 - x)K0.5Na0.5NbO3 - xBi(Mn0.5Ni0.5)O-3 ((1 - x )KNN- xBMN) with considerable charge-discharge characteristics and energy storage properties were prepared by a solid state method. Remarkable, a BMN doping level of 0.04, 0.96KNN-0.04BMN ceramic obtained good energy storage performance with acceptable energy storage density Wrec of 1.826 J/cm(3) and energy storage efficiency eta of 77.4%, as well as good frequency stability (1-500 Hz) and fatigue resistance (1-5000 cycles). Meanwhile, a satisfactory charge-discharge performance with power density P-D similar to 98.90 MW/cm(3), discharge time t(0.9) < 70 ns and temperature stability (30-180?) was obtained in 0.96KNN-0.04BMN ceramic. The small grain size ( & SIM;150 nm) and the high polarizability of Bi3+ are directly related to its good energy storage capacity. This work proposes a feasible approach for lead-free KNN-based ceramics to achieve high-energy storage and ultra-fast charge-discharge performance as well as candidate materials for the application of advanced high-temperature pulse capacitors.