scholarly journals The Enhancement of Energy Storage Performances via Combining Relaxor Behaviors With the Crucial Point of Solubility Limit

Author(s):  
Zhifeng Shi ◽  
Yaping Liu ◽  
Fei Guo ◽  
Shifeng Zhao

Abstract (1-x)(0.96Na0.5Bi0.5TiO3-0.04BiMnO3)-xLaMnO3 ternary solid solution films were fabricated by Sol-gel methods. It takes advantage of the large polarization from 0.96NBT-0.04BMO limit solid solution at crucial point of solubility limit to enhance energy density. And LaMnO3 was introduced to improve the energy storage efficiency via the enhancement of relaxor behaviors. It is shown that the relaxor behaviors had been enhanced, and a large energy storage density of 87.9 J/cm3 and efficiency of 56.5 % were achieved for 0.85(NBT-BMO)-0.15LM films, with increase ratio of 4.9 % and 13.3 % respectively than 0.96NBT-0.04BMO solubility limit films. However, when LaMnO3 is beyond a certain limit, the breakdown strength is reduced due the formation of the current channel. Thus it suggests a alternative method that combining relaxor behaviors with solubility limit films, which provides a way to regulate the energy storage performances for film capacitors.

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3585
Author(s):  
Xueqing Bi ◽  
Lujia Yang ◽  
Zhen Wang ◽  
Yanhu Zhan ◽  
Shuangshuang Wang ◽  
...  

Three-dimensional BaTiO3 (3D BT)/polyvinylidene fluoride (PVDF) composite dielectrics were fabricated by inversely introducing PVDF solution into a continuous 3D BT network, which was simply constructed via the sol-gel method using a cleanroom wiper as a template. The effect of the 3D BT microstructure and content on the dielectric and energy storage properties of the composites were explored. The results showed that 3D BT with a well-connected continuous network and moderate grain sizes could be easily obtained by calcining a barium source containing a wiper template at 1100 °C for 3 h. The as-fabricated 3D BT/PVDF composites with 21.1 wt% content of 3D BT (3DBT–2) exhibited the best comprehensive dielectric and energy storage performances. An enhanced dielectric constant of 25.3 at 100 Hz, which was 2.8 times higher than that of pure PVDF and 1.4 times superior to the conventional nano–BT/PVDF 25 wt% system, was achieved in addition with a low dielectric loss of 0.057 and a moderate dielectric breakdown strength of 73.8 kV·mm−1. In addition, the composite of 3DBT–2 exhibited the highest discharge energy density of 1.6 × 10−3 J·cm−3 under 3 kV·mm−1, which was nearly 4.5 times higher than that of neat PVDF.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3006
Author(s):  
Serge Nyallang Nyamsi ◽  
Ivan Tolj

Two-tank metal hydride pairs have gained tremendous interest in thermal energy storage systems for concentrating solar power plants or industrial waste heat recovery. Generally, the system’s performance depends on selecting and matching the metal hydride pairs and the thermal management adopted. In this study, the 2D mathematical modeling used to investigate the heat storage system’s performance under different thermal management techniques, including active and passive heat transfer techniques, is analyzed and discussed in detail. The change in the energy storage density, the specific power output, and the energy storage efficiency is studied under different heat transfer measures applied to the two tanks. The results showed that there is a trade-off between the energy storage density and the energy storage efficiency. The adoption of active heat transfer enhancement (convective heat transfer enhancement) leads to a high energy storage density of 670 MJ m−3 (close to the maximum theoretical value of 755.3 MJ m−3). In contrast, the energy storage efficiency decreases dramatically due to the increase in the pumping power. On the other hand, passive heat transfer techniques using the bed’s thermal conductivity enhancers provide a balance between the energy storage density (578 MJ m−3) and the energy efficiency (74%). The utilization of phase change material as an internal heat recovery medium leads to a further reduction in the heat storage performance indicators (142 MJ m−3 and 49%). Nevertheless, such a system combining thermochemical and latent heat storage, if properly optimized, can be promising for thermal energy storage applications.


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