Design and optimization of Miura-Origami-inspired structure for high-performance self-charging hybrid nanogenerator

A hybrid piezoelectric-triboelectric-electromagnetic nanogenerator (HPTENG-EMG) has been designed meticulously by focusing on material selection, structural design, and performance evaluation. The module can operate using three parts; piezoelectric, triboelectric and an electromagnetic mechanism. The hybrid concept of triboelectric and piezoelectric is achieved by fabricating triboelectric-piezoelectric composite materials working through the TENG mechanism. In the material design part, the composite film between bacterial cellulose (BC) and BaTiO3 nanoparticles (BT-NPs) fabricates and optimizes its properties with a suitable number of BT-NPs. The unique Miura-Origami (MO) hexagonal multilayer shape is applied within the structural design to increase the contact surface area, which enhances the electrical output signal. The third part of the hybrid system incorporates an electromagnetic generator (EMG) by designing a structure of compact and lightweight cylindrical tubes with magnetic levitation structures. The hexagonal multilayer shape of MO composite TENG (MO-CTENG) generates an open-circuit output voltage (VOC) of ∼414 V and short-circuit output current (ISC) of ∼48.3 μA with maximum output power (P) of about ∼6.94 mW. The highest ISC value of ∼38 mA can be promoted in the optimized EMG, which is higher than the MO-CTENG by ∼786 times. The practical application of this technology is demonstrated by human shaking motion for battery charging in the wireless Global Positioning System (GPS). The maximum direct current output voltage (VDC) saturation of 30 V can be achieved within 19 s. This work provides a potential methodology for increasing electrical output performance by capturing more mechanical energy through the conjunction of three phenomena into a single device, which exhibits a promising way of addressing an energy crisis

Towards the preparation of organic ferroelectric composites: fabrication of a gamma-glycine-bacterial cellulose composite via cold sintering process

The cold sintering process (CSP) has emerged as a revolutionary technique for low-temperature processing of ceramics and composites, enabling high-density fabrication at low temperatures. In this study, we demonstrated the implementation of CSP in fabricating the γ-glycine (γ-G)-bacterial cellulose (BC) composite and evaluated the effect of sintering temperature and holding time on the microstructure and electrical properties. Our findings revealed that an increase in sintering temperature and holding time leads to grain growth, as the transient solvent (water) facilitates the closely-packed microstructure. Moreover, the addition of BC as a filler into the γ-G matrix leads to a composite with a 10% increase in hardness when BC was uniformly distributed in γ-G. The composite with a relative density of 97% was successfully obtained at 120 °C/24 h, preserving the γ polymorph of glycine without the unwanted transformation commonly observed with traditional sintering. We also reported the dielectric and ferroelectric properties of the γ-G-BC composite, exhibiting a remanent polarization of 0.004 μC/cm2 and a coercive field of 1.201 kV/cm. Our findings suggest that CSP is a promising approach for low-temperature processing and fabrication of ceramics, especially when incorporating structurally sensitive filler such as organic ferroelectric, to achieve high-performance composites