Maximum Energy Storage Research Articles

Near-complete extraction of maximum stored energy from large-core fibers using coherent pulse stacking amplification of femtosecond pulses

High field science relies on ultrashort pulse lasers with multi-joule pulse energies for studying light–matter interactions under extreme conditions and for driving particle accelerators and secondary radiation sources of x rays, gamma rays, neutrons, positrons, muons, and protons. Next-generation laser drivers will require a 103−104 times increase in pulse repetition rates, producing multi-joule energies at multi-kilowatt average powers to enable practical applications in nuclear engineering, advanced materials, medicine, biology, homeland security, and high-energy physics. Spatially coherently combined femtosecond fiber lasers are recognized as a pathway to these next-generation drivers, with significant practical advantages including high efficiency and the possibility of compact integration. However, chirped pulse amplification in fibers is capable of extracting only a small fraction (usually ∼1%) of the maximum stored energy. Here we demonstrate near-complete maximum stored energy extraction with low accumulated nonlinearity from a large-core fiber amplifier using coherent pulse stacking amplification. We have amplified a 81-pulse stacking burst in a 85 µm core chirally coupled core Yb-doped fiber, extracting up to 9.5 mJ (∼90% of stored energy) with <4.5 radians of accumulated nonlinear phase, temporally combined this burst into a single pulse, and achieved 4.2 mJ pulses of 313 fs bandwidth-limited duration after compression. This represents, to our knowledge, the highest energy extracted and compressed into a femtosecond pulse from a single fiber amplifier, enabling approximately two orders of magnitude size reduction of future high-energy coherently spatially combined fiber laser arrays.

Numerical modelling of energy storage using hydraulic fracturing in shale formations

In order to further expand the development of renewable energy, achieve low-carbon environmental protection, and promote the transformation of the oil and gas industry, this study introduces a new energy storage method: store energy by creating artificial fractures in shale formations. A fully coupled hydraulic fracturing numerical model is established to investigate the impact of various factors (Such as operational parameters, wellbore configurations, geological conditions, etc.) on energy storage capacity and energy storage efficiency. This study demonstrates that the energy storage efficiency is extremely sensitive to injection/flow-back rate and perforation number/diameter. Reducing the injection/flow-back rate or increasing the number/diameter of perforations can substantially improve energy storage efficiency. In general, deeper storage formation leads to higher energy storage capacity and higher energy output power. For abandoned shale wells, injection, and flow-back water have negligible impact on the transport of settled proppants. The proppant bank accumulated at the bottom of existing hydraulic fracture of depleted shale wells reduces effective fracture height, resulting in a reduction of maximum energy storage. Injecting high-viscosity fracturing fluid and flow-back can recover a portion of settled proppants and mitigate the adverse effect of proppants on energy storage.

Revealing multiphase coexistence of R-O-T phases in BaTiO3-CaTiO3-BaSnO3 electroceramics for energy harvesting and storage response with piezo actuation

The (Ba1-xCax)(SnyTi1-y)O3 piezoelectric ceramics (where x=0.016, y=0.024; x=0.032, y=0.048; x=0.048, y=0.072; x=0.064, y=0.096; x=0.08, y=0.12) were designed by conventional solid state reaction method. The crystal structure for the composition of x=0.064 and y=0.096 (abbreviated as BCST-4) possesses the coexistence of non-centrosymmetric rhombohedral-orthorhombic-tetragonal (R-O-T) tri-lattice symmetries at room temperature, as demonstrated by the structural Rietveld refinement, Raman analysis, and temperature dependence of dielectric study. Because of the R-O-T multiphase coexistence, BCST-4 possesses a superior electromechanical and piezoelectric property viz. kp ∼ 0.45, strain ∼ 0.100 %, d33* ∼ 649 pm/V, and an improved d33 ∼ 452 pC/N, which is comparable to commercially available soft PZT ceramics (d33 ⁓ 370 pC/N). For BCST-4 ceramics, an exceptional electrostriction coefficient Q33 ∼ 0.0434 m4/C2 value was attained. The intrinsic piezo-actuation DC strain was observed to be 130 microstrain (με) and 188 με with ε33 and ε31 modes respectively. The BCST-4 ceramic exhibits a maximum output power of 1.03 mW, a power density of 13.5 µW/mm3, a maximum output current of 88 µA, and an open circuit voltage Vpp of 28 V which successfully glowed ‘SPPU’ panel having 40 red commercial light-emitting diodes (LEDs). The energy storage study reveals that BCST-4 ceramics exhibit a maximum energy storage density (Wrec) of 165.87 mJ/cm3 with efficiency (ƞ) 68.00 %. Therefore, the improvement in electrostriction coefficient, piezoelectric charge coefficient, and energy storage response indicates that BCST-4 ceramic has the potential for actuator, energy harvesting, and energy storage applications.

Shape Optimization for Lithium-Ion Battery with Porous Electrodes

In this presentation, we introduce a gradient-based shape optimization framework to design porous electrodes for maximum energy storage. Lithium-ion batteries are becoming an increasingly important energy source and storage device. Large surface area that advocates high reaction rates often leads to small porosities that deteriorate electrochemical transport, which significantly restricts ion penetration depth, limiting the material utilization in planar electrodes. Consequently, architected electrodes are required to optimize performance.We consider a model with two materials, namely porous electrode and pure electrolyte. Density-based topology optimization with continuous material volume fraction has previously been implemented on lithium-ion battery system for both half-cell and full-cell model to maximizes its energy storage. Despite the capability of producing complex interdigitated structures, an appropriate penalization scheme for intermediate materials is required for the optimizer to provide near binary designs. Setting up such a penalization is often time-consuming due to the large number of design-dependent variables that affect the forward model differently. Alternatively, the shape optimization approach used in this work produces binary designs naturally by morphing conformal meshes, circumventing inaccuracies associated with fuzzy interfaces. Shape sensitivities are computed via the adjoint method and leveraging automatic differentiation. The optimization problem is solved using a nonlinear programming technique.In this presentation, we perform shape optimization on a half-cell model to maximize its energy storage when a fixed charging current is applied. We study multiple arrangements of physical parameters and compare their performance against a monolithic electrode. Both 2D and 3D results are presented.

A novel microgroove-based absorber for sorption heat transformation systems: Analytical modeling and experimental investigation

This study proposes a novel sorber bed design, a stationary thin film microgroove-based absorber, that can address the low specific power and oversized sorber bed issues in existing oscillatory solid sorption heat transformation systems. An analytical heat and mass transfer model is developed for the proposed stationary thin film microgroove-based absorber. A highly-wettable microgrooved aluminum substrate is fabricated by the deposition of a hybrid Al2O3/TiO2 layer, and experimental water uptake measurements are obtained using a custom-built gravimetric large pressure jump setup to validate the analytical model. The model examines how key design parameters affect specific cooling power, cooling power density, and energy storage density. Findings indicate that cycle time and groove depth significantly impact system performance. Also, it is found that there is an optimum groove depth, or film thickness, to achieve maximum power. Trapezoidal grooves achieve higher specific cooling power and cooling power density, while rectangular grooves yield a higher maximum energy storage density. It is experimentally shown that a specific cooling power enhancement of up to 600 % can be obtained compared to the experimental data available for oscillatory sorber beds. Also, the absorption rate of the present sorber bed is up to three times higher than that of falling film absorbers.

Synthesis and Characterization of 3D MnNi2O4@MnNi2S4/NF-MOF-67-rGO nanoflower@nanosheet for ultra-high capacity electrode material

Abstract This study reports a novel 3D MnNi2O4@MnNi2S4/NF-MOF-67-rGO core-shell nanoflower@nanosheet synthesized at very high temperature and pressure shows an outstanding electrode substance for ultra-high super capacitor. The structure of MnNi2O4@MnNi2S4 was determined by using infrad red spectrum, scanning electron microscopic images and cyclic voltammetric techniques. The core (MnNi2O4) and shell (MnNi2S4) are both dynamic resources and they are involved in the Faraday redox processes to make possible the MnNi2O4@MnNi2S4 conducting device to acquire more electrochemical properties. The power capacitance of the MnNi2O4@MnNi2S4 electrode material reaches 805.09 C g−1 while the density of the current is 1.0 A g−1. Furthermore, the preservation rate of specific capacity of the MnNi2O4@MnNi2S4 electrode reaches 91.50% after the five thousand charge - discharge cycles while the density of current is 20.0 A g−1. The energy density for the MnNi2O4@MnNi2S4//AC material attains 74.64 Wh kg−1 at a energy density of 774.05 Wh kg−1. In addition, the MnNi2O4@MnNi2S4 //AC shows exceptional self-discharge properties. Therefore, the MnNi2O4@MnNi2S4 conducting device presents wide-ranging utilities and applications for capacitors of the battery-type. In this work, a novel 3D MnNi2O4@MnNi2S4 /NF-MOF-67-rGO core-shell nano arrangement was effectively grown-up on the Nickel foam via the reaction mixture growth technique, which misplaced the conductive additive and addition of binder and the complex method of electrode fabrication. It is quite remarkable that the maximum energy storage capacity of the 3D MnNi2O4@MnNi2S4/NF-MOF-67-rGO reaches 3579.60 F g−1 at the current density of 1.0 A g−1 and 1008.50 F g−1 at the current density of 20.0 A g−1. At a given density of current of 15.0 A g−1, the retention rate of maximum energy storage capacity reaches 94.10 % after 5 cycles, showing excellent cycling performances.

Effect of sepiolite on the rheological properties of shear thickening fluid and improvement mechanism analysis

To improve the performance of shear thickening fluids (STFs), we propose the addition of fibrous sepiolite. Through macroscopic rheological tests and microscopic characterization, the effects of different sepiolite mass fractions (0 wt%, 1 wt%, 2 wt% and 3 wt%) on the shear thickening of a SiO2-STF system (with a PEG200 dispersion medium) at different ambient temperatures (20 °C, 30 °C, 40 °C and 50 °C) were investigated. Rheological experiments revealed a significant improvement in the shear thickening of SiO2-STF with the addition of sepiolite (Sep/SiO2-STF), with 7.11- and 1.94-fold increases in absolute and relative shear thickening, respectively. As the sepiolite mass fraction increased from 0 wt% to 3 wt%, the temperature sensitivity coefficient decreased from 13.493 to 4.839, indicating that the Sep/SiO2-STF system still exhibited favourable shear thickening at 50 °C. Dynamic oscillatory shear testing revealed that with an increase in sepiolite mass fraction from 0 wt% to 3 wt%, the maximum energy storage modulus, maximum energy dissipation modulus and shear stress increased by 5196.25 %, 1676.16 % and 377.54 %, respectively. Microscopic characterization revealed that sepiolite induced the formation of more clusters in the STF system primarily through the physical adsorption of silica particles and Si–OH on its surface, leading to a significant increase in the shear thickening effect.

Dielectric and energy storage properties of (Ba0.2Sr0.2Na0.2Ca0.2La0.2)(ZrxTi1‐x)O3 high‐entropy ceramics and thin films

AbstractA series of (Ba0.2Sr0.2Na0.2Ca0.2La0.2)(ZrxTi1‐x)O3 (BSNCLZxT1‐x) (x = 0, 0.05, 0.1, 0.15, and 0.2) high‐entropy ceramics were prepared in forms of bulks and thin films by conventional sintering and spin‐coating, respectively. All ceramic bulks and thin films are composed of a single perovskite‐structured solid solution. The introduction of the Zr element reduces the dielectric loss of bulks and thin films and improves the frequency stability of the dielectric constant. The ceramic bulks have a higher dielectric constant and lower loss than their corresponding thin films. As x rises from 0 to 0.2, the breakdown strength Eb of the ceramic bulks increases from 209 to 327 kV/cm, and that of thin films enhances from 890 to 1770 kV/cm. The bulks and thin films of BSNCLZ0.1T0.9 possess the maximum recoverable energy density Wrec (0.82 and 3.48 J/cm3) and energy storage efficiency η (95.8% and 86.8%).

Sandwich-structured SrTiO3/PEI composite films with high-temperature energy storage performance

Dielectric capacitors are widely used in aerospace and power systems due to their non-polluting, high power density and fast charge/discharge rates. Polyetherimide (PEI) exhibits excellent temperature tolerance, high withstand voltage and low dielectric loss. However, its relatively low dielectric constant restricts its energy storage density. In this paper, a sandwich-structured composite film with the outer layer of pure PEI and the middle layer of strontium titanate (SrTiO3)/PEI is prepared by the solution casting method. At room temperature, the composite film with 5 vol% two-dimensional (2D) SrTiO3 plates achieves an outstanding energy storage density of 19.46 J cm−3 and an ultra-high energy storage efficiency of 97.05% under an electric field of 630 MV m−1. Furthermore, this composite film exhibits a maximum energy storage density of 10.34 J cm−3 and an energy storage efficiency of 88.13% at 150 °C. Combined with finite element simulation results, it confirms that the synergistic effect of 2D SrTiO3 plates and sandwich-structured can effectively hinder the development of electric trees. This work presents a sophisticated approach to design and preparation of dielectric composites suitable for the applications of high-temperature energy storage.

Design of maximum power point energy storage and inverter for photovoltaic power generation

With the increasing tension of fossil energy in the world and the damage to the environment caused by the use of fossil energy, new energy led by solar energy has been paid much more attention by countries around the world. If the efficiency of solar energy is improved, it will bring breakthrough changes to the world’s energy structure. Based on the related applications of solar photovoltaic power generation, this paper designs an independent photovoltaic power generation system with energy storage device. In the form of DC/DC conversion, the system uses the maximum power point tracking technology of photovoltaic cells to realize the efficient use of solar energy during the charging process. The system inverts the DC voltage after the storage, realizing the transformation of DC voltage to 220 V AC voltage, to realize the utilization of energy in various aspects.

Moderation of [Bi3+/Na1+] molar ratio for enhancement of dielectric and energy storage properties of NaNbO3 ceramics

Lead-free (Na1−3xBix)(Nb0.75Ti0.25)O3 (x = 0.0, 0.05, 0.1, 0.125 and 0.15) (NN-BT) ceramics were synthesized using solid-state reaction technique. The effect of Bi3+ into the crystal structure, dielectric, ferroelectric and energy storage properties of NNT ceramics were investigated. Pure NNT shows present perovskite structure with orthorhombic crystal structure at x ≤ 0.125, while Na3NbO8-NaNbO3 composite phase has been detected at x = 0.15. The tolerance factor (τ) decreased from 0.97 (x = 0.0) to 0.82 (0.15) which signified the composition deviated from perovskite structure at 0.15. Significant enhancement of dielectric constant at room temperature has been achieved by increasing Bi-content and the maximum value (∼1500) obtained at 0.1. The largest value of maximum polarization (Pmax) and smallest value of remnant polarization (Pr) were achieved at x = 0.1 due to orthorhombic NaNbO3 and rhombohedral (Na0.5Bi0.5)TiO3 coexistence phases. The substitution of monovalent (Na1+) by trivalent (Bi3+) lead to create sodium vacancies into the A-sites of NNT lattice subsequently increased the cations disorder and charge misfit. The maximum recoverable energy storage density (Wrec = 17.5 J cm−3) and energy storage efficiency (η = 80%) were achieved at x = 0.1, E ∼ 700 kV cm−1. Partially, (NNTB0.1) exhibit an outstanding stability of energy storage properties in terms of temperature range (25 to 150 °C) and frequency stability (2–20Hz). The present results imply the moderation ratio of Bi/Na plays an important role for enhancement of energy storage properties of NaNbO3 anti-ferroelectric ceramics.

Nanoporous PANI/ZnO/VO2 ternary nanocomposite and its electrolyte for green supercapacitance

The green process of energy storage by utilizing the by-product obtained after the synthesis of PANI54.69 %: ZnO7.81 %: VO237.50 % (PZnV) nanocomposite by insitu single step method, as its electrolyte is demonstrated herein. This green approach yields 23 % improvement in the energy storage compared to that in the presence of 1 M H2SO4. The enhanced energy storage obtained for PZnV nanocomposite in the presence of acidified by-product are a specific capacitance (Cs) of 177.3 F g−1, a specific capacity (Q) of 212.7 C g−1, an energy density (E) of 35.46 W h kg−1 (comparable with E of lead acid batteries), and a power density (P) of 1.632 kW kg−1 at 1 A g−1. The PZnV exhibited an unique feature of increase in energy storage with increase in No. of CV cycles in the presence of 1 M H2SO4, and the maximum energy storage was achieved after 12,312 cycles with a Cs of 440.5 F g−1, a Q of 528.6 C g−1, an E of 88.10 W h kg−1 (comparable with E of Li-ion batteries), and a P of 2.154 kW kg−1. A good cyclic stability up to 16,812 cycles was achieved at 0.4 V s−1.

A novel system of liquid air energy storage with LNG cold energy and industrial waste heat: Thermodynamic and economic analysis

Liquid air energy storage (LAES) is a promising technology for large-scale energy storage applications, particularly for integrating renewable energy sources. While standalone LAES systems typically exhibit an efficiency of approximately 50 %, research has been conducted to utilize the cold energy of liquefied natural gas (LNG) gasification. This approach, applied during the LAES energy storage phase of air compression and liquefaction, can reduce the power consumption of the compressor and enhance the performance of the integrated system. However, the improvement in the system's efficiency is constrained due to the low temperature of the air entering the turbine expansion during the energy release phase. Most studies only focus on the utilization of LNG cold energy, neglecting the proper utilization of the cold energy generated during the liquid air gasification process. This paper proposes an integrated system of LNG cold energy utilization and cement industry waste heat recovery (WHR) with LAES (LNG-LAES-WHR). A thermodynamic model is constructed, and the system is optimized by using four-stage compression, four-stage expansion, and R601 as the working fluid for WHR. The optimized integrated system has a round-trip efficiency (RTE) of 176.27 % and achieves a power output of 337.53 MW. Compared to the previously proposed system, this system has a high exergy efficiency of 74.49 % with a maximum energy storage capacity of 0.5918 kW/kg LNG. The economic analysis shows that the system has the best economic performance when constructed in Zhuhai: the dynamic payback period (DPP) is 4.2 years and the life cycle net present value (NPV) is 1170.72 million USD. This system realizes the cascaded utilization of energy, both in terms of heat and cold, which is safe, flexible, and highly efficient. This work provides a reference for the design of integrated systems for large-scale LAES for industrial applications.

Energy-storage performance of NaNbO3-based ceramic capacitor derived from a high DOP glass network structure

0.75(0.4Na2O-0.1K2O-0.5Nb2O5)-0.25(0.87SiO2-0.13BaO) glass-ceramics were prepared by a traditional melting method to optimize the crystallization kinetics. We obtained a glass network with high degree of polymerization (DOP) by crystallization at different temperatures and achieved a high energy storage density. The increase of crystallization temperature has promoted the precipitation of ferroelectric phases Na0.9K0.1NbO3 and NaNbO3 with high dielectric constant (1200–2000), promoted the increases of grain size from 0.76 μm to 1.33 μm, and reduced the gap width from 3.71eV to 3.22eV. When the crystallization temperature increased to 1000°C–1100 °C, Ba2NaNb5O15 with low dielectric constant (∼460) increases, grain boundaries appear, and dielectric constant and BDS decrease. Among all the samples, the sample crystallized at 900 °C showed homogeneous and dense microstructure (grain size∼0.91 μm). The experimental data confirmed that the glass sample crystallized at 900 °C achieves low dielectric loss (<0.005) and high dielectric constant (∼122). The glass sample crystallized at 900 °C sample had a maximum energy storage density of 3.65 J/cm3, a power density of about 54 MW/cm3 and a super-fast discharge speed of 38 ns at 660 kV/cm.

Numerical study of the melting rate enhancement of nano phase change material in a modified shell and tube heat exchanger

The current investigation employs numerical analysis using ANSYS Fluent software to explore the melting behaviour of phase change material (PCM) and nano-PCM in a semi-circular shell and tube heat exchanger, utilizing dual side heating for enhanced conduction and convection rates of heat transfer. The study incorporates aluminium oxide nanoparticles at volume concentrations of 2 %, 4 % and 6 % within paraffin wax and assessing their impact on melting and thermal energy storage rates. Notably, the 2 % nanoparticle volume concentration exhibits an enhanced storage rate as compared to higher concentrations. The increase in nanoparticle concentration from 0 % to 2 %, 2 % to 4 % and 4 % to 6 % results in percentage reduction in melting time of 21 %, 3.51 % and 2.8 % respectively. Semi-circular configuration shows significant improvement in the energy storage rate as compared to the circular triplex tube configuration. The maximum energy storage rate of PCM for the semi-circular and circular configurations is 1.15 kW and 1.04 kW respectively, marking a 9.56 % increase over the circular configuration. Moreover, the semi-circular and circular configurations using nano-PCM achieve a maximum energy storage rate of 1.19 kW and 1.14 kW, representing a 4.20 % increase over the circular configuration.

Real-time outdoor experiment and performance analysis of dual-coil heat exchanger integrated thermal energy storage

Integrating a thermal energy storage system into a solar water heater enables a continuous heat supply to ensure hot water is available for household uses throughout the day. This research emphasizes integrating TES units into solar water heating systems. The overall performance of flat plate solar water heaters for a regular (conventional) solar water heating system and a solar water heating system integrated with TES using phase change material (PCM) are analyzed. This innovative design ensures efficient heat capture from the sun, storing it in the phase change material for later use, guaranteeing a sustainable and cost-effective solution for hot water needs. A split PCM tank is integrated within the solar water heating network for the second scenario and is made of a 25 L filled with a phase change material that acts as the thermal storage medium. The PCM tank has a dual-coiled heat exchanger to aid the heat transfer process with paraffin wax as the phase change material. The parameters that are looked into from the conventional and TES-integrated solar water heating systems include the water temperature profiles throughout the entire solar water heating networks and the PCM's temperature distribution throughout the day. A customized water draw schedule is adapted to represent the average hot water usage of a typical household in Kuala Lumpur. Findings reveal that the TES-integrated solar water heating system can be 21 % more efficient than the conventional system due to the lesser heat losses and prolonged hot water supply. The maximum efficiency obtained is about 82 %, and energy can be saved about 50 % from the electric heater. The maximum energy storage is at the 50 °C temperature controller's setting and is feasible for the existing conventional solar water heaters.

Enhanced energy-storage density in (Pb0.98La0.02)(Zr0.45-xSn0.55Hfx)0.995O3 antiferroelectric ceramics

Antiferroelectric ceramics with unique characteristics of electric-field-induced antiferroelectric to ferroelectric phase transitions and ultra-fast charging-discharging rate, which are demanded in high pulse power devices. In this work, (Pb0.98La0.02)(Zr0.45-xSn0.55Hfx)0.995O3 (PLZSH) antiferroelectric ceramics with x = 0∼0.20 were prepared via a conventional solid-state reaction approach. Incommensurate modulation structure with a 1/n<110> superlattice was observed in AFE at room temperature, which was associated with the unique domain boundaries, contributing the obvious declined AFE-FE phase transition electric field as well as the enhanced energy storage density. It was also observed that the maximum recoverable energy storage density (Wrec) increases from 2.93 J/cm3 (x = 0) to 5.72 J/cm3 (x = 0.15), and the corresponding energy-storage efficiency uprises from 82.4 % to 87.8 % with the increasing x at 280 kV/cm. The superior energy density and efficiency indicate that the obtained PLZSH antiferroelectric ceramics are promising for practical applications in pulse power devices.

Modeling and analysis of PCM‐encapsulated solar thermal energy storage system for space heating

AbstractIn this study, a phase change material (PCM)‐encapsulated packed‐bed thermal energy storage (PB‐TES) system is intended for Day‐round space heating in the winter. Solar concentric collectors act for day‐time heating and TES charging, while the stored energy can be used at night and intermediate time for space heating. A region‐wise techno‐economic analysis of PCM candidates is made to compare the costs and sizes of solar collectors and PB‐TES. A spherical capsule filled with sodium nitrite (NaNO2) and sodium nitrate (NaNO3) is numerically investigated during the PCM charging at constant thermal input. After complete liquefication, the charging time for NaNO2 and NaNO3 capsules is 3280 and 4300 s, respectively, holding the maximum stored energy of 733.4 KJ/kg at 285°C and 687.27 kJ/kg at 310.12°C, respectively. In addition, the stored exergy is obtained 238.78 and 234.74 kJ/kg for NaNO2 and NaNO3, respectively; however, the average exergetic effectiveness for NaNO2 and NaNO3 are 0.54 and 0.46. Despite the lower energy storage capacity (kJ/kg) of NaNO3, the PB‐TES volume is less with NaNO3 than with NaNO2 due to higher density. However, the average cost ($/tonne) of NaNO3 PCM is 50% higher than NaNO2. Subsequently, the thermal efficiency of the proposed system is estimated at 27.68% and 26.94% during day and night‐time operations.

Effect of BiFeO3 on the ferroelectric and energy storage properties of (Bi1/2Na1/2)0.94Ba0.06TiO3 based compositions

The compound of (1 − x)[(Bi1/2Na1/2)0.94Ba0.06TiO3)]–xBiFeO3 (BNBT–BF), (0 ≤ x ≤ 0.15) sintered ceramic was processed by chemical route. The XRD patterns revealed the formation of single structured perovskite of Bi1/2Na1/2TiO3 (BNT) ceramics. The temperature-dependent dielectric characteristics indicated different dielectric phase changes in the fabricated compounds. Ferroelectric P–E hysteresis loop showed temperature sweep variations in saturation (P) and residual polarizations (Pr). Storage density (w) increases with temperature. This is due to the presence of AFE (Antiferroelectric) phase at temperatures >120 °C. The energy storage efficiency (η) and the dielectric break down strength (DBS) of the samples were observed to decrease with BF doping. The maximum energy storage density (w) of 0.29 J/cm3 was observed for × = 0.15 at 60 kv/cm.

Exploration of temperature driven conduction process and ferroelectric properties of Mn doped GdCrO3

This work delivers the research findings of the temperature dependent DC resistivity, AC impedance and ferroelectric polarization of GdCr1−xMnxO3 (x = 0 and 0.3). Mixed valence states of Cr (Cr3+ and Cr4+) are explored using the x-ray photoelectron spectroscopy analysis. The exponential decay of DC resistivity on escalating the temperature advocates the semiconducting-like nature for the probed samples. The DC resistivity data of these samples fit well into small-polaron hopping and variable range hopping models. The impedance attributes of these samples were scrutinized over a broad spectrum of temperatures at selected frequencies. The values of the real and imaginary parts of impedance unveil substantial reduction on raising the temperature, thereby signifying the increase in conductivity of the samples. Pristine sample displays an electrical relaxation peak at 65 °C, which translates towards the lower temperature at higher frequencies. Further, the semicircular behavior of Nyquist plots at higher temperatures indicates the reduction of the charge transfer resistance. The equivalent circuits of Nyquist plots are generated using Z-view software. From these plots, it is perceived that grain boundary resistance upsurges while the grain resistance and capacitance drops upon doping. The ferroelectric measurements reveal that the coercive field (Ec) values decrease whereas the values of maximum polarization (Pm), remnant polarization (Pr) and energy storage increase in 30% doped GdCrO3. These observations establish that electrical and ferroelectric properties of GdCrO3 system can be tuned with appropriate Mn doping.