BaTiO3 Particles Research Articles

Exploring barium-titanium-peroxo-hydroxide as an excellent single-source precursor for crystallographically diverse barium titanate ceramics – parametric study

Barium-titanium-peroxo type amorphous materials gained importance with the advent of wet-chemical methods for the production of crystalline perovskite barium titanate (BaTiO3) electroceramics. In this paper, the chemical nature of the barium-titanium-peroxo precursor was determined by means of elemental (EPMA), spectroscopic (FT-IR and FT-Raman), XRD and thermal (DSC and TGA/DTA) analyses. Several synthesis parameters such as the barium source, the peroxide treatment time, the reaction temperature and the reaction time were investigated. The precursor was also thermally treated at varying temperatures between 30 °C and 1000 °C. Relatively high reaction temperatures are detrimental to the Ba∙O∙Ti structure, resulting in plain TiO2 formation. Though relatively low temperatures (ice bath) are needed to suppress unwanted TiOCl2, ambient synthesis conditions and short reaction time (2 h) resulted in the desired single-source properties, i.e. amorphous Ba∙O∙Ti-peroxo structure with Ba/Ti ratio of unity (1.04 ± 0.04). The addition of an extra stirring step during H2O2 addition lowered the chance of carbonate incorporation in the precursor. Thermal analysis under air and nitrogen atmosphere was performed and a stoichiometric formula of Ba2,08Ti2O(O2)1,9(OH)5,3∙3,1H2O was calculated, which was in very good agreement with literature data. The barium-titanium-peroxo-hydroxide material proved to be an excellent single-source precursor. Phase-pure, highly crystalline and facetted, stoichiometric BaTiO3 particles with differently crystallographically oriented facets were obtained via the molten-salt solid-state method ({100} or {111} oriented facets) as well as the hydrothermal route ({100} oriented facets).

Relaxor-like behavior of the dielectric response of dense ferroelectric composites

We study experimentally and theoretically the influence of size effects and structural factors on the dielectric and ferroelectric properties of the dense ferroelectric composites. The composites have the form of the tape-casted films with 28 vol% of nanosized or submicron BaTiO3 particles dispersed in the polyvinyl butyral. We measured and analyzed the temperature dependences of the capacitance and dielectric losses in the temperature range (−200 – +200)oC and frequency range (102–105) Hz. The nonmonotonic temperature dependences of dielectric permittivity of the studied composite films have a wide plateau-like maxima located between 80oС and 160oС, in contrast to the relatively sharp maximum near the Curie temperature (∼124oC) observed in the fine-grained and coarse-grained ceramics, sintered from the same nanosized or submicron BaTiO3 particles at 1250oC. The shift of the dielectric permittivity and losses maxima (in more than 40oC) and their strong frequency dispersion do not agree with the behavior expected for the systems with a weak interaction between ferroelectric particles and a polymeric matrix. In contrast, we reveal the relaxor-like behavior of the composite dielectric response. To explain the observed results, we propose the analytical model, which considers the strong dipole-dipole cross-interaction of the BaTiO3 particles in the dense nanocomposite. The analytical model is corroborated by the structural studies of the BaTiO3 nanosized and submicron particles by X-ray phase analysis and static 137Ba NMR spectra, as well as by the finite element modelling of the composite polar properties, which confirms the strong cross-interactions between the dipole moments of single-domain nanoparticles and/or between the domain walls of different submicron polydomain particles.The obtained results may be useful for development of cheap and flexible lead-free dense ferroelectric nanocomposites with relaxor-like behavior of the dielectric response, which are promising for non-volatile memory and energy-saving elements, modulators, electrical converters and piezoresistive elements.

Impact of graphite nanoflakes and gamma radiation on the mechanical, electrical, and thermal properties of EPDM/modified BaTiO3 composites

The effect of graphite nanoflakes (GNFs)/modified barium titanate (MBT) hybrid fillers on the mechanical, electrical, and thermal properties of ethylene-propylene-diene monomer (EPDM) was extensively investigated in the current study. Moreover, the effect of gamma irradiation on the different properties of the prepared nanocomposites was investigated. To accomplish this goal, EPDM/MBT composites with various GNFs contents (0, 2, 4, 6, and 8 phr) were fabricated using a conventional roll mill. Graphite was expanded by heating and subsequently modified using tween 80 surfactant, resulting in the formation of GNFs. The presence of various functional groups on the surface of the modified BaTiO3 particles was verified by Fourier transform infrared spectroscopy (FTIR). The scanning electron microscopy (SEM) analysis revealed a uniform dispersion of GNFs in EPDM/MBT composites, with a concentration up to 6 phr. The study revealed that the mechanical properties of the nanocomposites were reinforced by the inclusion of GNFs up to 6 phr. The irradiated EPDM/MBT/6 phr GNFs nanocomposite exhibited the maximum elastic modulus value of 4.8 MPa, which was approximately 32 % higher than that of the corresponding unirradiated nanocomposite. The thermal conductivity of the irradiated EPDM/MBT/8 phr GNFs nanocomposite increased from 0.213 W/m.K to 0.260 W/m.K (22 %), while the dielectric constant increased from 4.475 to 5.551 (24 % increase) at 103 Hz as compared to the pure EPDM/MBT composite. The enhanced electric and thermal performance of GNFs can be attributed to the mobility of their π-electrons.

3D high-temperature resistance BaTiO3/EG hybrids with enhanced EMWs absorption capacity

BaTiO3 is a promising electromagnetic waves (EMWs) absorption material due to its chemical stability and large dielectric constant. However, the high reflection coefficient of pure BaTiO3 at high frequencies reduced its EMWs absorption capacity. To resolve the issue, BaTiO3/expanded graphite (EG) hybrids were successfully synthesized by high-energy ultrasound assisted heat treatment technology. The combination of BaTiO3 particles and layered EG formed three-dimensional (3D) heterostructure of BaTiO3/EG hybrids, which optimized the impedance matching. Abundant conductive network enhanced interfacial polarization, numerous interface defects and multiple reflections together promoted the attenuation of EMWs. At the molar ratio of 0.2:0.8 between BaTiO3 and EG, the BaTiO3/EG sample with 1.5 mm match thickness displayed −100.6 dB of minimum reflection loss (RLmin) and 5.9 GHz of effective absorption bandwidth (EAB). In addition, the ceramic character of BaTiO3/EG hybrids endowed them excellent high-temperature stability.

Spatially-resolved in-situ/operando structural study of screen-printed BaTiO3/P(VDF-TrFE) flexible piezoelectric device

The incorporation of lead-free BaTiO3 particles into P(VDF-TrFE) provides a versatile way for tuning dielectric and piezoelectric properties. Screen-printing enables the easy production of flexible capacitors. To prevent particle aggregation, the BaTiO3 particles are functionalized with a surfactant. Initially, 60 % vol. BaTiO3 particles are deposited in the second layer out of three layers. After annealing and cooling, the particle distribution is successfully homogeneous in the whole film. After poling at 80 °C, the relative permittivity and the piezoelectric coefficient d33 significantly increase up to 159 and 8 pC/N respectively. In situ/operando spatially-resolved X-ray techniques allow exploring the structural evolution of the composite device during annealing and during an applied electric field. The application of an electric field leads to the quasi-disappearance of the P(VDF-TrFE) ferroelectric state. As a matter of fact, the interactions between the P(VDF-TrFE) and the surfactant may limit the rotation of P(VDF-TrFE) chains near the particles. Hence, paraelectric polymers could be chosen on a mechanical or economic basis for the matrix in piezoelectric composite devices. Regarding BaTiO3, the lattice strain evolves from an extrinsic strain at RT to an intrinsic strain after annealing and cooling. At the cooled state, the tetragonality c/a is higher than 1.01, leading to improved piezoelectric properties. The increase of the average domain size leads to the increase of the composite permittivity. Finally this knowledge facilitates the development of tailored flexible piezoelectric composite devices.

Polybutylene adipate terephthalate (PBAT) composites for thermally conductive, fire retardant, high dielectric applications using BaTiO3 and MWCNTs as fillers

This study provides a comprehensive investigation of the fabrication of novel composite materials by blending polybutylene adipate terephthalate (PBAT) with barium titanate (BaTiO3) and multiwalled carbon nanotube (MWCNT) fillers. Prior to fabricating the composites, the filler surface treatments were tailored to enhance their compatibility with the PBAT matrix. Adipic acid (AA), a monomer for PBAT, was employed on the surface of the BaTiO3 particles, while butanediol (BD) also a monomer of PBAT was used to modify the surface of the MWCNTs to ensure effective interaction with the PBAT chains during the composite fabrication process. The composite samples were produced by melt-blending at 140 °C, followed by injection molding at the same operating temperature for subsequent analysis. The results revealed remarkable improvements in the dielectric constant, thermal conductivity, fire retardancy, and tensile strength of the 40 wt% BaTiO3 and MWCNT-PBAT blends compared to pure PBAT. The incorporation of BaTiO3 additionally contributed to enhanced fire retardancy, mechanical properties, and dielectric properties, making the composite material more resistant to ignition and flame spread, thus rendering it suitable for applications requiring elevated fire safety. In addition, the inclusion of MWCNT improved thermal conductivity, enabling promising and efficient heat dissipation in various applications.

Orally Ingested Self-Powered Stimulators for Targeted Gut-Brain Axis Electrostimulation to Treat Obesity and Metabolic Disorders.

Obesity is a significant health concern that often leads to metabolic dysfunction and chronic diseases. This study introduces a novel approach to combat obesity using orally ingested self-powered electrostimulators. These electrostimulators consist of piezoelectric BaTiO3 (BTO) particles conjugated with capsaicin (Cap) and aim to activate the vagus nerve. Upon ingestion by diet-induced obese (DIO) mice, the BTO@Cap particles specifically target and bind to Cap-sensitive sensory nerve endings in the gastric mucosa. In response to stomach peristalsis, these particles generate electrical signals. The signals travel via the gut-brain axis, ultimately influencing the hypothalamus. By enhancing satiety signals in the brain, this neuromodulatory intervention reduces food intake, promotes energy metabolism, and demonstrates minimal toxicity. Over a 3-week period of daily treatments, DIO mice treated with BTO@Cap particles show a significant reduction in body weight compared to control mice, while maintaining their general locomotor activity. Furthermore, this BTO@Cap particle-based treatment mitigates various metabolic alterations associated with obesity. Importantly, this noninvasive and easy-to-administer intervention holds potential for addressing other intracerebral neurological diseases.

Contrasting piezocatalytic and tribocatalytic behavior of BaTiO3

In this work, BaTiO3 with different morphologies is obtained by controlling the Ba/Ti ratio in the precursor, reaction temperature, and reaction time. The effects of the morphology and the specific surface area of samples, as well as friction conditions on piezocatalytic and tribocatalytic performance, are investigated. BaTiO3 exhibits the best piezocatalytic performance when it is composed of a mixed-shape of BaTiO3 rod and particle because in this case there is a balance between the specific surface area and the piezopotetial. However, the tribocatalytic performance is majorly dependent on friction conditions such as the roughness of the reaction vessel and the rotation speed of the stirring rod. Both ⋅O2− and ⋅OH play important roles in the piezocatalytic and tribocatalytic degradation of dyes. Therefore, this work gains significant factors in piezocatalytic and tribocatalytic degradation of dyes and provides a reference for remediation of water pollution in the future.

3D Printing of Flexible BaTiO3/Polydimethylsiloxane Piezocomposite with Aligned Particles for Enhanced Energy Harvesting.

With the rapid development of human-machine interactions and artificial intelligence, the demand for wearable electronic devices is increasing uncontrollably all over the world; however, an unsustainable power supply for such sensors continues to restrict their applications. In the present work, piezoelectric barium titanate (BaTiO3) ceramic powder with excellent properties was prepared from milled precursors through a solid-state reaction. To fabricate a flexible device, the as-prepared BaTiO3 powder was mixed with polydimethylsiloxane (PDMS) polymer. The BaTiO3/PDMS ink with excellent rheological properties was extruded smoothly by direct ink writing technology (DIW). BaTiO3 particles were aligned due to the shear stress effect during the printing process. Subsequently, the as-printed composite was assembled into a sandwich-type device for effective energy harvesting. It was observed that the maximum output voltage and current of this device reached 68 V and 720 nA, respectively, for a BaTiO3 content of 6 vol %. Therefore, the material extrusion-based three-dimensional (3D) printing technique can be used to prepare flexible piezoelectric composites for efficient energy harvesting.

Hybrid nanogenerator for self-powered object recognition

Energy harvesting systems, including piezoelectric (PENG), triboelectric (TENG), and pyroelectric (PYNG) nanogenerator technologies, have emerged as one of the major future energy solutions. Energy harvesting eliminates the need for conventional batteries and encourages eco-friendly alternatives. This study reports hydrothermally synthesized BaTiO3 (BTO) particles with a tetragonal symmetry for hybrid energy harvesting. BTO particles are incorporated with PDMS at various wt% to form a flexible composite film. The 15 wt% BTO-PDMS composite/Al hybrid device (PENG-TENG) produces a peak voltage of 100 V, a current of 980 nA, and a charge of 17 nC, generating a peak power output of 33.64 μW at 100 MΩ. Furthermore, integrating this HNG (external hybridization) yielded an output of 101 V and 980 nA, demonstrating practical applicability. HNG is also employed to interact by touching various objects at different temperatures. The pyroelectric behavior of BTO allows direct thermal sensing of the object. The signals produced are processed using a convolutional neural network (CNN)-based object recognition system, which achieved a remarkable classification accuracy of 99.27% for various objects. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications. This research paves the way for developing hybrid energy harvesters and can be employed further for extremely precise battery-free object recognition systems. This unique hybrid nanogenerator, which combines pyroelectric, piezoelectric, and triboelectric components, represents a new method of self-powered object detection. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications.

Fabrication and properties evaluation of chitosan/BaTiO3 composite membranes for the periodontitis treatment

Periodontitis gradually damages the hard and soft tissues surrounding the tooth, leading to tooth loss. In recent years, the use of biomaterials in periodontitis treatment has expanded, including gels, nanoparticles, microparticles, fibers, and membranes. Among these, membranes have more clinical applications. Due to the ability of the piezoelectric material to regenerate damaged tissues, the aim of this study was to create piezoelectric composite membranes. To achieve this, Barium titanate powder (BaTiO3 powder)—a piezoelectric substance—was synthesized using the hydrothermal method and analyzed with X-ray diffraction (XRD) and Field emission scanning electron microscopy (FESEM). Four types of membranes were fabricated using solvent casting method: three composite membranes with chitosan matrix and BaTiO3 fillers (at 3%, 6%, and 9% weight), and one chitosan membrane without BaTiO3. The microstructure of the membrane surfaces, agglomeration of BaTiO3 in membranes, and hydrophilicity, antibacterial, and electrical properties of the membrane were also investigated. The results indicated that membranes containing 3 and 6% BaTiO3 had suitable surface structure for the periodontitis treatment. Agglomeration of BaTiO3 particles was higher in the membrane containing 9% BaTiO3. The large amount of BaTiO3 improved the antibacterial properties of the membranes. Additionally, the membranes containing BaTiO3 had high electrical properties, especially those with 3% and 6% BaTiO3. Therefore, composite membranes containing BaTiO3, especially membranes containing 6% BaTiO3, are more favorable options than those without BaTiO3 for periodontitis treatment.

Piezoelectric thin Film Composites with BaTiO3 for Microelectronics

The piezocomposites from poly-(vinylidene fluoride) (PVDF) with BaTiO3 (BT) are largely presented in literature, but the composites from polydimethylsiloxane (PDMS) with BT consist a very new scientific preoccupation. The novelty of the paper lies in a new simpler route of preparation of the two composites with PDMS and respectively PVDF matrix, with tailored deposition on specific substrates for microelectronic use (e.g. indium-tin-oxide ITO/glass, Si/Pt, polyethylene terephthalate PET), along with an extensive comparation of their dielectric features, a consistent comparison of the influence of polymer matrix upon the piezoelectric features, and a demonstration of direct use for microelectronic applications of the composites of BT with PDMS. An interesting effect is observed around 100 kHz domain, determined by the activity and architecture of BT particles mainly for the BT-PDMS composites, which induce an additional ionic-dipolar conjugated polarization, as a displacement due to the balance between the resonance and anti-resonance frequency. Such phenomena explain the potential use of such composites as resonators/filters, and BT-PDMS composites should be further investigated for tailored applications in radiofrequency electronic field. We can appreciate that superior piezoelectric features are offered by the composites of BT with PDMS, comparing to the composites with PVDF, which means that the composites of BT with PDMS were worth to study, leading to more versatile variants of electronic characteristics and with superior values.

Microwave-Assisted Cladding of Ni-BaTiO3 Mixture onto SS-304 for Enhancing the Wear Resistance and Surface Hardness

The present study focuses on achieving precise deposition of a Ni and 15% BaTiO3 particle mixture onto SS-304 substrates through meticulous preparation steps. Thorough cleaning of the SS-304 substrate eliminated contaminants, ensuring optimal adhesion. Simultaneously, the Ni-BaTiO3 mixture underwent preheating at 1200°C for 20 hours in a muffle furnace to eliminate moisture content, crucial for preventing coating defects. A uniform and crack-free cladding layer enhances the substrate’s resistance to wear, corrosion, and mechanical stresses, thereby extending its service life and improving overall functionality. The surface hardness of SS-304 experienced a substantial improvement of 39.90% following the cladding process with Ni and 15% BaTiO3. A sliding speed of 2 m/s was meticulously selected to replicate typical velocities encountered in practical applications, ensuring a realistic assessment of frictional behavior and wear resistance. Similarly, the sliding distance of 1000 m and an axial load of 5 N were precisely calibrated to simulate the mechanical stresses experienced during sliding contact, facilitating a thorough examination under relevant conditions. These carefully chosen parameters enabled the determination of key tribological properties essential for evaluating the performance of the cladded surface of SS 304 with Ni + 15% BaTiO3. The wear rate, measured at 0.0016 mm3/m, serves as a critical indicator, revealing the volume of material lost per unit distance of sliding. This parameter provides invaluable insights into the surface’s wear resistance and durability, crucial for assessing the longevity and performance of the cladded surface under abrasive conditions. Additionally, the coefficient of friction, determined to be 0.255, offers a quantitative measure of the surface’s frictional behavior during sliding contact.

Electro-mechanical actuation modulates fracture performance of soft dielectric elastomers

Soft dielectric elastomers respond to electric stimuli by undergoing large deformations and changes in their material properties. The actuation with deformable electrodes attached to the material originates Coulomb and dipole forces that convert the electric field into a mechanical response. Applications at large deformations can entail crack onset and propagation. Within this context, the response of a soft polymer to an applied electric field may serve to influence the fracture behavior of such materials, potentially enhancing it. Here we explore the fracture performance of an ultra-soft dielectric elastomer. To do so, we conduct tensile tests while applying electrical actuation on samples with pre-cuts. Additionally, we examine the elastomer filled with piezoelectric BaTiO3 particles to ameliorate the fracture performance beyond the limits observed in the unfilled material. In conjunction with the experiments, we employ a bespoke fracture phase-field model to analyze the stress triaxiality near the crack tip. The results indicate that the electric actuation induces beneficial crack tip blunting and stress de-concentration, enhancing the fracture toughness up to a 125% and delaying crack propagation. Our work provides a route for applications of soft dielectric elastomers that require improved fracture properties or, more broadly, the modulation of fracture behavior.

Numerical simulations of reactive cold sintering of BaTiO3

Numerical simulations of reactive cold sintering of BaTiO3 are performed under the experimental condition of Guo et al. It is suggested that amorphous BaTiO3 particles are produced first by chemical reactions and subsequent nucleation from the aqueous solution according to the Ostwald’s rule of stages. For the case of cold sintering under 300 °C and 500 MPa, the amorphous particles are transformed into crystalline particles partly during the initial heating stage by a simple thermal excitation when the particle size is less than about 5 nm and partly during cold sintering under high pressure through coalescence with other crystalline particles. For the case of 150 °C in sintering temperature, on the other hand, appreciable amounts of amorphous particles remain even after the cold sintering due to the incomplete sintering. The calculated grain sizes almost agree with the experimental data, which supports the present numerical simulations.

Improvement of thermo‐mechanical and dielectric properties of poly(lactic acid) and thermoplastic polyurethane blend composites using a graphene and BaTiO3 filler

AbstractThis study focuses on the development of composite materials using thermoplastic polyurethane (TPU) and poly(lactic acid) (PLA) with fillers such as barium titanate (BaTiO3) and graphene. Suitable surface treatment of filler particles is applied to activate the fillers to enhance the compatibility between the fillers and polymer matrix. Specifically, the BaTiO3 particles are hydroxylated and treated with glycidyl methacrylate (GMA), which acts as a compatibilizer between the two matrix polymers. On the other hand, the graphene particles are hydroxylated and treated with isophorone diisocyanate (IPDI), which reacts with the TPU soft segment chains during composite fabrication. The composite samples are fabricated via melt‐blending at 190°C, followed by mini molding at the same operating temperature for subsequent analysis. The results demonstrate a three‐fold improvement in the dielectric constant of 40 wt.% BaTiO3 and graphene–TPU–PLA blends composites relative to that of the neat TPU, along with an improved tensile strength. The tensile strength improvement is attributed to the support of the TPU matrix against the low ductility of the PLA. The thermal conductivity was doubled as compared with the neat TPU–PLA matrix for the 40 wt.% BaTiO3 and graphene–TPU–PLA blends.Highlights Composites of TPU–PLA–graphene and BaTiO3 filler particles were fabricated. The melt blending technique was employed to fabricate the composite. The dielectric constant was analyzed at both constant and variable frequencies. Thermal conductivity was doubled (40 [graphene + BaTiO3])

Microwave-assisted construction of AgIO3/BaTiO3 heterostructure with excellent photocatalytic activity for tetracycline and methyl blue degradation

A series of AgIO3/BaTiO3 composite photocatalysts were synthesized by a microwave-assisted hydrothermal method. Among obtained samples, ABO-2 exhibited superior catalytic performance toward the photocatalytic degradation of TC (30 mg/L) with a degradation rate reaching 76.2% within 40 min. Scanning electron microscopy and transmission electron microscopy demonstrated the formation of smaller spherical particles of BaTiO3 on the AgIO3 surface with a direct Z-type heterojunction. Photoluminescence indicated weaker fluorescence response intensity of the composite ABO-2, suggesting effectively suppressed recombination of electron-hole pairs. The impact of pH and inorganic anions on the removal of pollutants by ABO-2 was discussed in detail by degradation experiments. Experimental evidence obtained from free radical active species capture experiments and electron spin resonance (ESR) spectroscopy tests revealed that h+ and •O2− are the primary active species. The intermediates of the TC degradation process analyzed by liquid chromatograph mass spectrometer (LC-MS), as well as the potential degradation pathways and mechanisms were all studied. The photodegradation experiments under sunlight demonstrated ABO-2 achieving a degradation rate of 74.4% toward MB (10 mg/L) within 75 min, indicating a promising composite catalyst for practical applications.

Enhancing Dielectric Properties, Thermal Conductivity, and Mechanical Properties of Poly(lactic acid)-Thermoplastic Polyurethane Blend Composites by Using a SiC-BaTiO3 Hybrid Filler.

A composite of polymer blends-thermoplastic polyurethane (TPU) and poly(lactic acid) (PLA)-and BaTiO3-SiC was fabricated. BaTiO3 particles were used to improve the dielectric properties of the composite materials, whereas SiC was used to enhance thermal conductivity without altering the dielectric properties; notably, SiC has a good dielectric constant. The surfaces of the filler particles, BaTiO3 and SiC particles, were activated; BaTiO3 was treated with methylene diphenyl diisocyanate (MDI) and SiC's surface was subjected to calcination and acid treatment, and hybrid fillers were prepared via solution mixing. The surface modifications were verified using Fourier transform infrared spectroscopy (the appearance of OH showed acid treatment of SiC, and the presence of NH, CH2, and OH groups indicated the functionalization of BaTiO3 particles). After the extruded products were cooled and dried, the specimens were fabricated using minimolding. The thermal stability of the final composites showed improvement. The dielectric constant improved relative to the main matrix at constant and variable frequencies, being about fivefold for 40% BaTiO3-SiC-TPU-PLA composites. Upon inclusion of 40 wt.% MDI functionalized BaTiO3-SiC particles, an improvement of 232% in thermal conductivity was attained, in comparison to neat TPU-PLA blends.

Excellent energy storage performance with outstanding thermal stability assisted by interfacial resistance of aramid-based flexible paper capacitors

Polymer-based dielectric energy storage capacitors show more potential than conventional rigidity ceramic-based capacitors. Recent studies were classified into two categories: the excellent room temperature performance in poly (vinylidene fluoride) (PVDF) systems and the enhanced thermal stability in polyimide-based systems. Only now, however, both of them are still far from commercial use because of their inferior heat resistance or poor processability. By adding BaTiO3 (BT) particles in maturely used aramid nanofibers, we synthesized the aramid nanofiber (ANF)/BT-based flexible paper capacitors through a convenient industrialized technology in this work. Due to the intrinsic laminated structure of ANF and the uniform distribution of BT particles, the composite film with BT addition of 8 vol% exhibits outstanding dielectric thermal stability. With the help of the interfacial resistance in the organic–inorganic interface, which protected the ANF matrix from being breakdown too early by optimizing the electrical field distribution, a high and stable energy storage density of 6.70 J/cm3 was obtained in ANF/BT5. In addition, excellent energy storage frequency stability with ultrafast discharge speed was also achieved. This work offered a highly repeatable way to synthesize commercially used flexible capacitors, bridging the lab investigation and commercial use in high-power density energy storage polymers.

Impact of stirring regime on piezocatalytic dye degradation using BaTiO3 nanoparticles

There is increasing demand to use readily accessible waste energy to drive environmentally friendly processes. Piezocatalysis, the process of converting mechanical energy such as vibration into a chemical process, is a breakthrough next generation approach to meet this challenge. However, these systems currently focus on using ultrasound to drive the chemical reaction and are therefore expensive to operate. We show that by using simple mechanical stirring and BaTiO3 particles we can remove Rhodamine B dye molecules from solution. After evaluating a range of stirring parameters, we demonstrate that there is an interplay between stirring speed, volume of liquid, catalyst structure and rate of dye removal. Our maximum degradation rate was 12.05 mg. g−1 catalyst after 1 h of mechanical stirring at favourable conditions. This development provides a new insight into a low energy physical technique that can be used in environmental remediation processes.