Application of the Supercapacitor for Energy Storage in China: Role and Strategy

Supercapacitors are widely used in China due to their high energy storage efficiency, long cycle life, high power density and low maintenance cost. This review compares the differences of different types of supercapacitors and the developing trend of electrochemical hybrid energy storage technology. It gives an overview of the application status of supercapacitors in China’s smart grid and Energy Internet in detail. Some strategies and constructive suggestions are put forward to solve the existing problems. With the improvement of the grid-connected capacity of new energy power generation during the 14th Five-year Period of China, the supercapacitor market in China will usher in a good development opportunity. The role of the supercapacitor in achieving carbon peak carbon neutralization is prospected.

The Effect of α-Al2O3 Composite on Energy Storage Characteristics of the Orthogonal Phase PLZST Antiferroelectric Ceramics

The effect of (1-x)(Pb0.97La0.02)(Zr0.675Sn0.285Ti0.04)O3-xAl2O3, with x=0~0.04, 0.08, 0.10 composite ceramic samples was studied. In this experiment, the PLZST powder was pre-fired to obtain the perovskite structure, and then combined with α-Al2O3 to increase the BDS of the ceramic. The test results show that the composite thick film samples are all perovskite orthorhombic phases, and Al2O3 is mainly filled in the grain gaps with a flaky structure. A proper content of composite Al2O3 can increase the density of ceramics. With x=0.02, the maximum value of BDS is 25.27 kV/mm, which is 60% higher than pure PLZST material, and the releasable energy storage density also reaches a maximum of 2.95 J/cm³. After the composite amount exceeds 0.03, the saturation polarization intensity decreases significantly. The energy storage efficiency of each sample is generally not high, all of which are less than 65%.

Epoxy-Based/BaMnO4 Nanodielectrics: Dielectric Response and Energy Storage Efficiency

Compact capacitive energy storing/harvesting systems could play a key role in the urgent need for more energy-efficient technologies to address both energy and environmental issues. Therein, the purpose of the present work is to develop and investigate epoxy/BaMnO4 nanocomposites at various filler concentrations, which could be applicable as compact materials systems for energy storage and harvesting. Broadband dielectric spectroscopy was used for studying the dielectric properties and the relaxation processes of the examined nanodielectrics. The energy storing/retrieving ability of the nanocomposites was also evaluated via DC charge–discharge experiments. The coefficient of energy efficiency (neff) was found for all prepared nanocomposites to evaluate the energy performance of the systems. Dielectric data divulge the existence of two matrix-related relaxations, i.e., α-mode and β-mode, attributed to the glass-to-rubber transition of the polymer matrix and re-orientation of polar side groups, respectively. Interfacial polarization was also identified in the low-frequency and high-temperature region. The 7 phr BaMnO4 nanocomposite exhibits the best performance in terms of the stored and harvested energies compared to all systems. On the other hand, the 5 phr, 3 phr and 1 phr nanocomposites display optimum energy performance, reaching high values of neff.

Investigation of the coupling effect of flexoelectricity and ferroelasticity on energy storage efficiency of relaxor ferroelectrics

The Ginzburg–Landau theory and dipole defect model have been employed to investigate the flexoelectric and ferroelastic effects on the ferroelectric and energy storage properties of relaxor ferroelectrics (RFs). The results obtained show that due to the existence of polar nanoregions (PNRs) in RFs, the elastic field of the material, which is induced by both the flexoelectric and ferroelastic effects, leads to the increase of the domain switching energy and coercive field and the decrease of the energy storage efficiency. In contrast, the short-range electric field induced by the dipole defects enhances the energy storage efficiency of the material by enhancing the material’s relaxor behavior. Hence, the energy storage efficiency of RFs can be effectively functionalized by modulating the composition ratio and the electric field of the RF materials.

Synthesis and Properties of Inositol Nanocapsules

Sugar alcohols are phase−change materials with various advantages but may suffer from leakage during applications. In this study, inositol nanocapsules were synthesized at various conditions, including the amount of precursors and the time for adding the precursors. The effects of synthesis conditions on the properties of the nanocapsules were studied. The morphology, chemical composition, microstructure, phase−change characteristics and size distribution of the nanocapsules were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT−IR), transmission electron microscope (TEM), differential scanning calorimeter (DSC) and a zeta potential analyzer. The results confirm that inositol was well−encapsulated by an SiO2 shell. The shell thickness increased, while the supercooling degree of the nanocapsules decreased with increasing time for adding the precursors. In order to obtain nanocapsules with good morphology and phase−change characteristics, the time for adding the precursors should increase with the amount of precursors. The nanocapsules with the best properties exhibited high melting enthalpy, encapsulation ratio and energy storage efficiency of 216.0 kJ/kg, 83.1% and 82.1%, respectively. The size of the nanocapsules was remarkably affected by the triethoxysilane (TES) amount.

Excellent Energy Storage Performance in NaNbO3-Based Relaxor Antiferroelectric Ceramics Under a Low Electric Field

NaNbO3-based antiferroelectric (AFE) ceramics have the prominent advantages of stable performance and low cost. However, its energy storage property is often remarkably limited by the hysteresis of the antiferroelectric to ferroelectric phase transformation. In this work, 0.88Na(Nb1 − xTax)O3–0.12Bi0.2Sr0.7TiO3 (x = 0–0.075) antiferroelectric ceramics were synthesized using a conventional mixed oxide route. Ta5+ were completely dissolved into the lattice of 0.88NaNbO3–0.12Bi0.2Sr0.7TiO3 to form a pure perovskite structure. With increased Ta content, the AFE orthogonal P phase was replaced by AFE orthogonal R phase progressively. Meanwhile, the dielectric constant curve showed relaxor-like properties. As a result, slender P–E curves with reduced hysteresis loss and decreased residual polarization were achieved. Interestingly, a large recoverable energy storage density (Wrec ≈ 2.16 J cm− 3) and high energy storage efficiency (η ≈ 80.7%) were obtained simultaneously under a low driving electric field of 15 kV mm− 1 at doping ratio (x) of 0.075. In addition, the 0.88Na(Nb0.925Ta0.075)O3–0.12Bi0.2Sr0.7TiO3 sample exhibited excellent temperature stability, indicating an ideal candidate in future pulsed power capacitor.