Candidates For Energy Conversion Research Articles

Synergistically Optimizing Pressure-Driven Energy Conversion and Energy-Harvesting Application via Modulating an Antiferroelectric-to-Ferroelectric Overlap Zone in Antiferroelectric Ceramics.

Dielectric ceramics with ultrahigh polarization and energy density are the core components used in next-generation pulse power generators based on explosive energy conversion. However, the low polarization of ferroelectric materials and high depolarized pressure hinder their development toward miniaturization, light weight, and integration, while antiferroelectric materials possessing larger nonlinear saturated polarization and rich phase structure are neglected in pulse power energy conversion. Here, an effective strategy of constructing antiferroelectric-to-ferroelectric overlap zone is achieved in binary system (1 - x)(Pb,La)(Zr,Ti)O3-xBa(Al1/2Nb1/2)O3 antiferroelectric ceramics to realize an excellent polarization of 41 μC/cm2 and a large depolarization efficiency of >99% under 150 MPa as well as a record high energy harvesting density of 2.5 J/cm3 under 400 MPa. The excellent comprehensive energy conversion and energy harvesting performance is mainly attributed to the strategy of antiferroelectric-to-ferroelectric overlap zone and improved microdomain density, at which orthorhombic-to-rhombohedral structure evolution is confirmed by transmission electron microscopy, piezo-response force microscopy, and Raman spectrum, resulting in substantially enhanced remanent polarization compared to ferroelectric ceramics. Besides, excellent temperature stability (∼180 °C) and optimized depolarization pressure also support that this binary system is a candidate for energy conversion and energy harvesting application. This work demonstrates that antiferroelectric-to-ferroelectric overlap based on antiferroelectric materials is an excellent strategy to develop dielectric materials with excellent depolarized polarization and energy harvesting density for energy conversion and harvesting.

Light-responsive bent-core liquid crystals as candidates for energy conversion and storage

We have assessed the potential of light-responsive bent-core liquid crystals as candidate materials for energy conversion and storage applications, and promoted isothermal phase transitions between columnar and smectic phases.

Magnetically separable porous titanosilicate/Fe3O4 hybrid nanocomposites with enhanced photocatalytic performance under UV light irradiation

Magnetically separable mesoporous titanosilicate-Fe3O4 (FTS) hybrid nanocomposite has been developed. The synthesized porous FTS were well characterized by various analytical techniques like XRD, field emission SEM, TEM, BET, FT-IR, and UV–Vis diffused reflectance spectra for morphological and chemical properties evaluation. FESEM and TEM results shows the growth of finely distributed Fe3O4 particles in the titanosilicate matrix, its porous FTS has a great influence on the electronic and optical properties. More significantly, the FTS nanocomposite exhibit enhanced photocatalytic activity for the degradation of methylene blue under UV light irradiation. The optimum photocatalytic activity of FTS15 at 15 wt% of Fe3O4 under visible light is almost 3.5 and fivefold higher than pure titanosilicate (TS) and pure Fe3O4 (FO) respectively. We conformed that synthesized FTS15 hybrid photo catalyst are highly stable even after five successive experimental runs by XRD spectra. The improved photocatalytic performance of the FTS15 hybrid nanocomposite under UV light irradiation was due to the synergistic effect of the pure TS and pure FO. Therefore, FTS15 hybrid photo catalyst is a promising candidate for energy conversion and environmental remediation.

Homogeneous Metal Nitrate Hydroxide Nanoarrays Grown on Nickel Foam for Efficient Electrocatalytic Oxygen Evolution

Developing facile routes for fabricating highly efficient oxygen evolution reaction (OER) electrocatalysts is in great demand but remains a great challenge. Herein, a novel molten salt decomposition method to prepare 3D metal nitrate hydroxide (MNH, M = Ni, Co, and Cu) nanoarrays homogenously grown on different conductive substrates, especially on nickel foam (NF) for OER applications, is reported. Compared with the as-prepared CoNH/NF and CuNH/NF, NiNH/NF presents a superior electrocatalytic OER activity and stability in an alkaline solution, with a very low overpotential of only 231 mV versus a reversible hydrogen electrode to deliver a geometrical catalytic current density of 50 mA cm-2 and a low Tafel slope of 81 mV dec-1 , outperforming most reported transition metal compound catalysts. Structural investigation after the OER process reveals the morphology integrity of the nanoarrays but the formation of metal oxyhydroxide (for NiNH and CoNH) or oxide (for CuNH) as the likely real active species. These metal nitrate hydroxide non-noble metal electrocatalysts can be prepared by an economical and simple method, with enhanced intrinsic activity and long-term stability and durability, which might be new candidates for energy conversion and storage applications.

Functionalized Silicate Supported TiO<sub>2</sub>-ZnO Nanocomposite Film and its Application in Simultaneous Photocatalytic Degradation of Toxic Molecules

The TiO2-ZnO nanocomposite materials ((TiO2-ZnO)NCM) with different molar ratios (Ti:Zn) was synthesized by chemical route and dispersed in functionalized silicate sol-gel matrix (Silicate/(TiO2-ZnO)NCM)). The as prepared Silicate/(TiO2-ZnO)NCM were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The dispersion of the small amount of (TiO2-ZnO)NCM in silicate sol-gel matrix paves the way for the preparation of solid-state thin film photocatalyst which is advantageous for the separation of the catalyst from solution, the substrates and the reaction products. The simultaneous photoinduced oxidation of methylene blue (MB) dye and reduction of Cr (VI) to Cr (III) was examined at different amine functionalized silicate sol-gel embedded (TiO2-ZnO)NCM films. The (TiO2-ZnO)NCM dispersed into the amine functionalized silicate sol-gel matrix (TPDT) exhibited enhanced photocatalytic activity when compared to the (TiO2-ZnO)NCM without the silicate sol-gel. The functionalized silicate sol-gel supported (TiO2-ZnO)NCM is a potential candidate for energy conversion and environment remediation and cleaning applications.

Evaluation and Modeling of Power Generator with Bimorph PZT Cantilever

ABSTRACTBattery, the traditional power source in present wireless remote sensor systems, has large volume and requires large amount of maintenance. Therefore, piezoelectric power generator has been studied for a potential alternative to battery by scavenging or harvesting energy from its operating environment. The efforts for investigating such piezoelectric device have been especially enhanced by the miniaturization requirement and low energy consumption of advanced devices as well as the sufficient vibration energy sources and its high conversion efficiency. To utilize piezoelectric material as energy conversion transducer, the device should be designed to operate with high efficiency and simple configuration. PZT (Lead Zirconium Titanate) is an excellent candidate for energy conversion because of its large piezoelectric constant and coupling coefficient.In this study, power generators based on bimorph cantilever structure were designed and fabricated using PZT ceramic benders due to accessible large strain or energy. The parameters influencing the output energy of piezoelectric bimorph cantilevers including the dimensions of the cantilever and the proof mass, the loading ways of the proof mass, and the resonant frequency of the cantilever were systematically investigated. The robustness of cantilever structure was also considered for implementing piezoelectric power conversion devices in harsh environments. The final optimal design was realized by considering the balance between the output power and the safety factor through numerical analysis. The energy density generated by the optimized piezoelectric devices was higher than 1 mW at 1-g vibration, which could be enough to operate microsensor systems. To broaden the operation conditions, multiple-resonant frequency device was also explored.