Aurivillius-Type SrBi4Ti4O15/PGA Composite Film-Based Flexible Triboelectric Nanogenerators for Energy Harvesting/Storage and Multipurpose Tap-Indication Transducer Applications.

Recent advancements in flexible triboelectric nanogenerators (TENGs) have widely focused on converting mechanical energy into electrical energy to power small wearable electronic gadgets and sensors. To effectively achieve this, an efficient energy-converted power management circuit is required. Herein, we report on Aurivillius-type strontium bismuth titanate (SrBi4Ti4O15) nanoparticles (SBT NPs)-loaded polyglucosamine (PGA) composite film-based flexible TENG to be used for energy harvesting/storage and biomechanical applications. Initially, SBT NPs were synthesized and then, different weight concentrations were loaded into PGA. The TENG devices were fabricated using different wt % composite films (SBT/PGA) and polydimethylsiloxane as positive and negative triboelectric layers, respectively, and aluminum was used as a conductive electrode attached to two tribo films. To evaluate the electrical output from the device, contact-separation operation mode was used. An optimized TENG consisting of 2 wt % SBT/PGA composite film produced the maximum electrical output voltage and current of approximately ∼239 V and ∼7.5 µA, respectively. Efficient TENG energy harvesting and storage circuits have been proposed for storing charges in capacitors and for operating electronic gadgets. The optimized TENG was employed to generate electrical energy from various biomechanical movements. Thereafter, the biodegradability of the composite film was also tested. The fabricated films were completely biodegraded within a few hours. Furthermore, the TENG was utilized as a tap-indication transducer for multipurpose switching applications.

Wireless Alerts and Data Monitoring from BNNO-MWCNTs/PDMS Composite Film-Based TENG Integrated Inhaler for Smart Healthcare Application.

In recent years, the implementation of energy-harvesting technology in medical equipment has attracted significant interest owing to its potential for self-powered and smart healthcare systems. Herein, the integration of a triboelectric nanogenerator (TENG) is proposed into an inhaler for energy-harvesting and smart inhalation monitoring. For this initially, barium sodium niobium oxide (Ba2NaNb5O15) microparticles (BNNO MPs) are synthesized via a facile solid-state synthesis process. The BNNO MPs with ferroelectricity and high dielectric constant are incorporated into polydimethylsiloxane (PDMS) polymer to make BNNO/PDMS composite films (CFs) for TENG fabrication. The fabricated TENG is operated in a contact-separation mode, and its electrical output performance is compared to establish the optimal BNNO MPs concentration. Furthermore, multi-wall carbon nanotubes (MWCNTs), a conductive filler material, are used to enhance the electrical conductivity of the CFs, thereby improving the electrical output performance of the TENG. The robustness/durability of the proposed BNNO-MWCNTs/PDMS CF-based TENG are investigated. The proposed TENG device is demonstrated to harvest electrical energy from mechanical motions via regular human activities and power portable electronics. The TENG is integrated into the inhaler casing to count the number of sprays remaining in the canister, send the notification to a smartphone via Bluetooth, and harvest energy.

Mechanical and Acoustic-Driven BiFeO3 Composite Films-Based Hybrid Nanogenerator for Energy Harvesting and Sensing Applications.

Nanogenerators for acoustic energy harvesting are still in the early stage of development, and many challenges such as the optimization of device structure and the design of efficient and sensitive materials need to be addressed. To solve the above-mentioned problems, herein, advancement in synthesized multiferroic material for hybridizing the nanogenerator and efficient harvesting of various energies such as acoustic, mechanical, and vibrational energies is reported. Initially, bismuth ferrate (BiFeO3 , BFO)-based composite films are prepared with high ferroelectric and dielectric coefficients. The hybrid nanogenerator (HNG) based on a 3D-printed structure has the highest electrical output which is further improved depending on the BFO loading concentration in the composite film. The 0.5 wt% BFO-loaded PVDF-based HNG offers the enhanced open circuit voltage, short circuit current, and charge density values of ≈30 V, ≈1 µA, and ≈10 µC/m2 , respectively. The optimized HNG is employed to harvest mechanical energy from everyday human life. Furthermore, the HNG layers are used in the fabrication of a multi-energy harvester/sensor (MEH/S) which can harvest/sense various vibrational and acoustic energies under different acoustic frequencies and amplitudes, respectively. The harvested energy from the MEH/S is tested to power portable electronics.

Multistage SrBaTiO3 /PDMS Composite Film-Based Hybrid Nanogenerator for Efficient Floor Energy Harvesting Applications.

Triboelectric nanogenerators are an emerging energy-scavenging technology that can harvest kinetic energy from various mechanical moments into electricity. The energy generated while humans walk is the most commonly available biomechanical energy. Herein, a multistage consecutively-connected hybrid nanogenerator (HNG) is fabricated and combined with a flooring system (MCHCFS) to efficiently harvest mechanical energy while humans walk. Initially, the electrical output performance of the HNG is optimized by fabricating a prototype device using various strontium-doped barium titanate (Ba1- x Srx TiO3 , BST) microparticles loaded polydimethylsiloxane (PDMS) composite films. The BST/PDMS composite film acts as a negative triboelectric layer that operates against aluminum. Single HNG operated in contact-separation mode could generate an electrical output of ≈280 V, ≈8.5 µA, and ≈90 µC m-2 . The stability and robustness of the fabricated HNG are confirmed and eight similar HNGs are assembled in a 3D-printed MCHCFS. The MCHCFS is specifically designed to distribute applied force on the single HNG to four nearby HNGs. The MCHCFS can be implemented in real-life floors with an enlarged surface area to harvest energy generated while humans walk into direct current electrical output. The MCHCFS is demonstrated as a touch sensor that can be utilized in sustainable path lighting to save enormous electricity waste.

Single-Electrode Triboelectric Nanogenerators Based on Ionic Conductive Hydrogel for Mechanical Energy Harvester and Smart Touch Sensor Applications.

Recent advancements in wearable electronic technology demand advanced power sources to be flexible, deformable, durable, and sustainable. An ionic-solution-modified conductive hydrogel-based triboelectric nanogenerator (TENG) has advantages in wearable devices. However, fabricating a conductive hydrogel with better mechanical and electrical properties is still a challenge. Herein, a simple approach is developed to insert ion-rich pores inside the hydrogel, followed by ionic solution soaking. The suggested ionic conductive hydrogel is obtained by cross-linking the polyvinyl alcohol (PVA) hydrogel and carboxymethyl cellulose sodium salt (CMC), followed by soaking in the ionic solution. Furthermore, a flexible and shape-adaptable single-electrode TENG (S-TENG) is fabricated by combinations of ionic-solution-modified dual-cross-linked CMC/PVA hydrogel and silicone rubber. Additionally, the effects of the CMC concentration, type of ionic solution, and concentration of optimized ionic solutions on the hydrogel properties and S-TENG output performance are studied systematically. The well-dispersed CMC- and PVA-based hydrogel provides ion-rich pores with high ion migration, leading to enhanced conductivity. The fabricated S-TENG delivers maximum output performance in terms of voltage, current, and charge density of ∼584 V, 25 µA, and 120 µC/m2, respectively. The rectified S-TENG-generated energy is used to charge capacitors and to power a portable electronic display. In addition to energy harvesting, the S-TENG is successfully demonstrated as a touch sensor that can automatically control the light and the speaker based on human motions. This investigation provides a deep insight into the influence of the hydrogel on the device performance and gives a guidance for designing and fabrication of highly flexible and stretchable TENGs.

High-Efficiency Poly(Vinylidene Fluoride-Co-Hexafluoropropylene) Loaded 3D Marigold Flower-Like Bismuth Tungstate Triboelectric Films for Mechanical Energy Harvesting and Sensing Applications.

Triboelectric nanogenerators (TENGs) are one of the most trending energy harvesting devices because of their efficient and simple mechanism in harvesting mechanical energy from the environment into electricity. Herein, ferroelectric and dielectric bismuth tungstate (Bi2 WO6 (BWO)) with a marigold flower-like structure is prepared via a hydrothermal method, which is embedded in poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), forming a PVDF-HFP/BWO composite polymer film (CPF) to fabricate TENGs. Generally, the ferroelectric materials exhibit a large piezoelectric coefficient, high electrostatic dipole moment, and high dielectric constant. The prepared PVDF-HFP/BWO CPF reveals a high polar crystalline ß-phase which leads to enhanced piezoelectric and ferroelectric properties of the CPF, thus resulting in the increased electrical performance of the fabricated TENG. The electrical output performance of the proposed TENG is systematically investigated by varying the amount of BWO material embedded in the PVDF-HFP polymer. The fabricated PVDF-HFP/2.5 wt% BWO CPF-based TENG device exhibits the highest electrical output performance. Additionally, the robust test of the TENG device is conducted to investigate the electrical performance for long-term durability and mechanical stability. Finally, the proposed TENG is operated as a self-powered sensor, harvesting mechanical energy from daily life human activities, and powering various low-power portable electronics.