Browsing by Author "Liu, Hanxing"

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    Enhanced dielectric breakdown strength and ultra-fast discharge performance of novel SrTiO3 based ceramics system
    (Elsevier, 2020) Jan, Abullah; Liu, Hanxing; Hao, Hua; Yao, Zhonghua; Marwa, Emanuel; Wengao, Pan; Atta, Ullah; Abdul, Manan; Amjad, Ullah; Minghe, Cao; Arbab, Safeer Ahmad
    The ceramics (1−x)SrTiO3-x (0.93Bi0.5Na0.5TiO3-0.07Ba0.94Sm0.04Zr0.02Ti0.98O3) abbreviated as ((1−x) ST -x (BNT-BSmZT)) (x = 0, 0.1, 0.2, 0.3) were synthesized via solid-state sintering route. The phase structure, microstructure, electrical properties and energy storage performances of the outlined compositions were investigated using X-ray diffraction, electron microscopy, and dielectric measurement techniques. The X-ray diffraction results reveal structural phase transformation from a perfect cubic structure to a rhombohedral structure as the x value increased from 0 to 0.3. The submicron grain size of ∼0.71 μm was obtained for x = 0.1. The rest of the parameters such as breakdown strength (BDS), energy storage performance, charge-discharge efficiency (η), discharging time, dielectric loss and electrical conductivity were observed to be affected by the homogeneous, compact microstructure and grain size. Herein we report an innovative ST-based lead free ceramics capacitor with the highest breakdown strength (BDS) of 420 kV/cm, an impressive recoverable energy density (Wrec) of 1.93 J/cm3, simultaneously with high efficiency (η) of 80.0%, moreover, low dielectric loss, low electrical conductivity ∼4.7 × 10−8 S/m at 100 °C and fast discharge time (∼0.18 μs) in x = 0.1. Our findings in this work suggest that the obtained ceramics system might be a promising candidate for pulsed power technology.
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    Enthralling storage properties of (1–x)La0.03Na0.91NbO3–xBi(Li0.5Nb0.5)O3 lead-free ceramics: high energy storage applications
    (American Chemical Society, 2020) Emmanuel, Marwa; Hao, Hua; Liu, Hanxing; Appiah, Millicent; Jan, Abdullah; Ullah, Atta; Ullah, Amjad
    The current work presents the designed series of compositions within pseudocubic regions based on (1–x)La0.03Na0.91NbO3–xBi(Li0.5Nb0.5)O3 ceramics abridged as (1–x)LNN–xBLN meant for energy storage applications. The addition of Bi(Li0.5Nb0.5)O3 (BLN) considerably disrupted the ferroelectric order of the La0.03Na0.91NbO3 (LNN) ceramics and favored the perfection of the energy storage density properties. Material properties like breakdown strength (BDS), charge–discharge efficiency (η), and dielectric loss of the system were enhanced via the incorporation of BLN into LNN. The external electric field supply into the system drastically enlarged the energy storage density, where the maximum recoverable energy density value of 2.02 J cm–3 at 300 kV cm–1 was achieved in 0.88LNN–0.12BLN ceramics. Besides this, the new system also demonstrates a strong ability to withstand stress (fatigue-free character) and sound temperature stability characteristics. The impressive storage density, temperature stability, cycle stability, and frequency stability credited to a steady relaxor pseudocubic phase covering a broad temperature range describes the newly designed system. The results demonstrate the potential for the (1–x)LNN–xBLN ceramics as the promising lead-free energy storage materials.
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    Significantly enhanced energy storage density of NNT ceramics using aliovalent Dy3+ Dopant
    (American Chemical Society, 2021) Emmanuel, Marwa; Hao, Hua; Liu, Hanxing; Jan, Abdullah; Alresheedi, Faisal
    Sodium niobate (NN)-based lead-free ceramic DyxNa1–x(Nb0.9Ta0.1)O3 denoted as (DNNT) x = 0, 0.05, 0.1, 0.2, and 0.3 was synthesized via a conventional solid-state method to achieve bulk lead-free dielectric ceramics having an improved energy storage capability that can conceivably be used in pulsed power technology. The addition of Dy3+ broadened the phase transition peak, thereby strengthening the relaxor properties of the DNNT ceramic materials. The sample’s microstructure was explored using a scanning electron microscope, and its corresponding phase structure via X-ray diffraction (XRD). A systematic study was carried out for energy storage properties of 0.2 mol of Dy3+ (DNNT20) where a recoverable energy storage density (Wrec) of 4.61 J cm–3 with a breakdown strength (BDS) of 478 kV cm–1 and an energy storage efficiency (η) of ≈84% were achieved. Additionally, the DNNT20 ceramics displayed comparatively reasonable temperature stability (20–140 °C), excellent frequency stability (0.1–100 Hz), and also fast charge–discharge speed (≤0.5 μs). Thus, the DNNT20 ceramic materials can be of probable use for future energy storage applications.