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In this paper, Co-doped Na3V2−xCox(PO4)2F3(x = 0,0.1,0.5,0.7) sodium ion battery anode material was prepared by one-step hydrothermal method, and Na3V1.5Co0.5(PO4)2F3 anode material coated with graphene was also prepared. It is confirmed that moderate Co2+ doping can improve the electrochemical performance of NVPF. Among all samples, Na3V1.5Co0.5(PO4)2F3@Graphene shows the best rate and cycle performance. It exhibits the highest specific capacity of 91.5 and 48.8 mAh/g at 1C, respectively when x = 0.5, after coating graphene, the charge-discharge specific capacities of 1C cycle are 128.2 mAh/g and 63.5 mAh/g for the first time, and 62.2 mAh/g and 45.1 mAh/g for 45 weeks.The performance results show that the excellent electrochemical performance of Na3V1.5Co0.5(PO4)2F3@Graphene can be attributed to the increase in electronic conductivity and ion diffusion coefficient. [ABSTRACT FROM AUTHOR]

The ferroelectric, lead-free perovskite sodium bismuth titanate-barium titanate (BNT-BT) has excellent electrical performance and is now recognized as a possible alternative material for lead zirconate titanate (PZT). It can be doped with some active elements to form a solid solution with a morphotropic phase boundary (MPB), where the solid solution has high dielectric properties and high energy storage performance. In this paper, the research results of BNT-BLT, BNT-BLZT, BNT-BSLZT, BNT-BMNLT and BNT-BST-KNN ceramic materials are summarized, and the influence of their doping mode on the phase structure and electrical properties are analyzed. The study found a rhombohedral and tetragonal phase coexistence region, where the tolerance factor value of ceramics is between 0.7530 and 0.7803. Moreover, the energy storage density of antiferroelectric ceramics increases with the expansion of the MPB region and is affected by the dielectric constant. [ABSTRACT FROM AUTHOR]

(1−x)Bi1/2Na1/2TiO3–xBa1/2Sr1/2TiO3–0.05KNaNbO3 (BNT–BST–KN, x = 0.01, 0.03, 0.05, 0.07) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state. The hysteresis loop of the ceramic at different temperature under 70 kV/cm electric field was analyzed. In this paper, the energy storage properties of BNT–BST–KNN ceramics are studied. It was found that the addition of Sr element helps to improve the electric field strength tolerance and the breakdown resistance performance the material, so as to improve its energy storage density. At room temperature, the P–E curves of the materials in the system basically show a double hysteresis loop, and with the increase of temperature, the characteristics of the double hysteresis curve are particularly obvious. The ceramics exist in the ferroelectric–antiferroelectric coexistence phase region near 303 K, namely the morphotropic phase boundary region. It shows that the ceramic has anti-ferroelectric characteristics at room temperature, and is a typical anti-ferroelectric material. [ABSTRACT FROM AUTHOR]

[(Bi1/2Na1/2)0.94Ba0.06](1–1.5x)LaxTiO3(BNT-BLT, x = 0, 0.02, 0.04, 0.06) lead-free anti-ferroelectric ceramics were synthesized by a conventional solid-state reaction method. The microstructure and the electrical properties of BNT-BLT were investigated. The X-ray diffraction patterns reveal that the BNT-BLT ceramic is constituted by a single perovskite structure phase. The average grain size of the ceramic samples gradually decreases with increasing La content, reducing the ferroelectric properties of the material and enhancing its anti-ferroelectric properties. TheP-Ehysteresis loops of BNT-BLT ceramics at an electric field of 36 kV/cm indicate that both the saturation polarization (Ps) and the remnant polarization (Pr) decrease as the La doping increases. These properties indicate that BNT-BLZT ceramics are a promising lead-free anti-ferroelectric material for applications in energy-storage capacitors. [ABSTRACT FROM PUBLISHER]

[(Bi1/2Na1/2)0.92Ba0.05La0.02][SnxZr(0.95-x)Ti0.05]O3(BNT-BLSZT, x = 0, 0.03, 0.06, 0.09) lead-free ferroelectric ceramics synthesized by a conventional solid-state reaction method exhibit high crystallinity and high density at 1150°C. The microstructure and the electrical properties of BNT-BLSZT were investigated. The X-ray diffraction patterns reveal that the BNT-BLSZT ceramic is constituted by a single perovskite structure phase. The average grain size of the ceramic samples slightly increases with increasing Sn content, TheP-Ehysteresis loops of BNT-BLZST ceramics at 50 kV/cm indicate that both the saturation polarization (Ps) and the remnant polarization (Pr) decrease with increasing Sn-doping. It shows that Sn-doping is useful to improve energy storage density of the ceramics. These properties indicate that BNT-BLZST ceramics are a promising lead-free anti-ferroelectric material for applications in energy-storage capacitors. [ABSTRACT FROM PUBLISHER]

(Bi0.46Na0.46Ba0.05La0.02)ZrxTi(1-x)O3(BNBLZT,x= 0.01, 0.03, 0.05, 0.07) lead-free anti-ferroelectric ceramics were synthesized by conventional solid-state reaction method. Microstructures and electrical properties of BNBLZT were investigated. Calculation from the X-ray diffraction results reveals that BNBLZT ceramic possesses a single perovskite structure phase. All BNBLZT ceramics show high density and the grain sizes decrease slightly with the addition of Zr concentration. In addition, theP-Ehysteresis loops measured at room temperature show that the largest energy-storage densityWmaxis 1.89 J/cm3. The temperature dependence of dielectric permittivity ϵrand dielectric loss tanδ illustrate that the addition of Zr can improve the piezoelectric properties of BNBLZT ceramics. [ABSTRACT FROM PUBLISHER]

Abstract: Energy-storage properties of [(Bi1/2Na1/2)0.94Ba0.06]La(1−x)Zr x TiO3 (BNT-BLZT, x=0, 0.02, 0.04, and 0.06) lead-free anti-ferroelectric ceramics fabricated via the conventional sintering technique were first investigated. Calculation from the X-ray diffraction results reveals that BNT-BLZT ceramic possesses a single perovskite structure phase. In addition, the P–E hysteresis loops measured at room temperature show that the BNT-BLZT (x=0.02) ceramics obtain the maximum P value of 37.5μC/cm2 and the largest energy-storage density W max is 1.58J/cm3. The temperature dependence of dielectric permittivity ε r and dielectric loss tanδ illustrate that the addition of Zr can improve the piezoelectric properties of BT-BLZT ceramics. These properties indicate that BNT-BLZT ceramics might be a promising lead-free anti-ferroelectric material for energy storage application. [Copyright &y& Elsevier]