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Simple Method for Enhancing Performance of the Bacterial Cellulose-Based Triboelectric Nanogenerator by Adding Conductive Interlayer

Surface charge density is a key factor that greatly enhances the performance of a natural-based triboelectric nanogenerator (TENG), which is essential for future sustainable sensing and harvesting devices. This work introduced a conductive interlayer between a main frictional layer and electrode. This approach can suppress the charge recombination rate and improve the amount of charges produced during the triboelectrification process. Bacterial cellulose (BC) film was selected as a main frictional layer for the TENG. A conductive nanomaterial, i.e. silver flake, was incorporated into the BC film as an intermediate layer for enhancing TENG performance. As firstly reported, the maximum electrical outputs for the multi-layer BC structure could be found when using silver flake/BC composite (ratio 1:5) as an intermediate layer, which has 122 V and 8.2 µA of output voltage and current, respectively. This is higher than the output voltage and current of a single layer BC TENG by approximately 3 and 8 times, respectively. The maximum output power of ∼440 µW is achieved by connecting with a load resistor of ∼10 MΩ. This demonstrates an efficient strategy for designing a high performance energy harvester by adding an intermediate layer for the target of practical purposes in sustainable systems.

Dielectric and Improved Energy-Storage Properties in A-Site Nd3+ Doped Lead-Free 0.88NaNbO3-0.12Sr0.7Bi0.2TiO3 Ceramics

Sodium niobate (NaNbO3)-based antiferroelectric (AFE) ceramics have received significant attention for energy storage applications because of their good performance, low cost, and nontoxicity. However, the existence of the antiferroelectric P phase at room temperature causes large hysteresis, resulting in reduced energy storage efficiency. In this study, 0.88NaNbO3–0.12Sr0.7Bi0.2TiO3 ceramics doped with Nd3+ (i.e., 0.88Na1-3 x Nd x NbO3-0.12Sr0.7Bi0.2TiO3) at x = 0.0 − 0.025 were prepared via conventional solid-state mixed oxide route. The XRD data showed that all samples exhibited an orthorhombic structure. With increasing Nd3+ doping content, the antiferroelectric P (Pbma) phase to R (Pnma) phase transition temperature (T P-R) shifted to lower temperatures. Consistent with the dielectric properties, a transition to a relaxor-like slim P-E loop indicative of an AFE R phase was observed at the composition x ≥ 0.01. This led to an increase in both the recoverable energy-storage density (W rec) and efficiency (η) with an increasing amount of Nd3+ doping level. The maximum recoverable energy storage density (W rec = 0.54 J/cm3) and high energy storage efficiency (η = 93%) were observed at x = 0.025 under an applied electric field of 100 kV/cm. In addition, the optimum composition at x = 0.025 also exhibited excellent temperature stability from 25 °C to 150 °C. This research demonstrates that the NN–SBT–xNd system has the potential for use for high-energy-density pulsed power capacitor applications.

The Properties of Bi2O3 Additive on Radiation Shielding and Elastic Moduli Properties of TeO2–P2O5 Based Glass System

The radiation shielding and elastic moduli properties of (60–x)TeO2–30P2O5–xBi2O3 (x increased from 10–50 mol% in 10 mol% increments) glass series have been discussed. The radiation shielding quantities such as mass attenuation coefficient (µ m), effective atomic numbers (Z eff), half value layer (HVL) and mean free path (MFP) were calculated using Phy–X/PSD program at energies ranging from 1 keV–100 GeV while exposure and energy absorption buildup factors (EBF and EABF) were evaluated using geometric progression (G–P) fitting method at energies ranging 0.015–15 MeV for penetration depths (PD) until 40 mean free path (mfp). In addition, the density and elastic moduli were estimated. The results found that the TPB5 glass sample having the largest content of Bi2O3 possessed the highest density and excellent radiation shielding properties. This reflected that replacing TeO2 with Bi2O3 improved effective radiation shielding. In addition, the MFP for glass series were lower than the hematite-serpentine concrete. It indicated that this glass series are photon shielding better than the hematite-serpentine concrete. Whereas, this sample had the lowest elastic moduli. These results indicated that Bi2O3, a network modifier, has broken glass network bonds and formed non–bridging oxygen (NBOs) which affects the elastic moduli of the glass system.