Sustainable Energy Harvesting Research Articles

Triboelectric power generation performance of polyvinyl alcohol using ZnO–CuO–AgO trimetallic nanoparticles

AbstractTriboelectric nanogenerators (TENGs), a new technology for gathering sustainable energy, have attracted much scientific interest. In this study, we describe a unique method for modifying the triboelectric power generation performance of Polyvinyl Alcohol (PVA) by adding ZnO–CuO–AgO (ZCA) trimetallic nanoparticles to improve the performance of TENGs and answer the requirement for ecologically benign and biodegradable materials. Hydrothermal synthesis adopted to create ZnO–CuO–AgO trimetallic nanoparticles ensures a distinctive structure with a large surface area, essential for enhancing triboelectric power generation. From the AFM results, it is evident that 1% PVA/ZCA showed the highest output voltage of 0.27V. Despite following the general trend, at higher concentrations of ZCA nanofiller in the PVA matrix, the enhancement of output voltage is not observed, which can be attributed to the non-uniform distribution. The effect of spin-coated film thickness and nanoparticle concentration on the triboelectric performance of the PVA nanogenerator is studied by monitoring the open-circuit voltage in response to various mechanical stimuli. Finally, the developed biodegradable nanogenerators in this study can be used for sustainable energy harvesting applications such as wearable electronics, self-powered sensors, and environmental monitoring systems.

Assessment of Ecofriendly Zeotropic Working Fluids in Organic Rankine Cycle for Renewable Energy Harvesting

The shift toward renewable energy has drawn significant attention to zeotropic mixtures in the organic Rankine cycle (ORC). However, synthetic zeotropic mixtures are detrimental to the environment due to high global warming potential. In this context, this study explores the potential of natural zeotropic binary mixtures as an alternative to synthetic zeotropic mixtures in a transcritical ORC system. The performance of two natural zeotropic mixtures and three synthetic zeotropic mixtures (hydrofluorocarbons, hydrofluoroolefins) are analyzed and compared using turbine inlet pressure and carbon dioxide (CO2) concentration as objective functions. The comprehensive thermodynamic analysis focuses on energy (first‐law) and exergy (second‐law) efficiencies, heat transfer, environmental performance, and economic aspects. The thermal and exergy efficiencies of the natural zeotropic mixture consistently outperform other mixtures by a maximum of 8% and 18%, respectively, for the conditions studied. The net power‐to‐environmental impact ratio of natural zeotropic mixture outweighs other zeotropic mixtures by more than 50%. The heat transfer analysis also favors natural zeotropic mixture at CO2 concentrations below 60% while maintaining cost parity with synthetic zeotropic mixtures. The results emphasize a holistic approach involving performance, heat transfer, environmental impact, and cost as parameters while choosing zeotropic mixtures for sustainable energy harvesting.

Cellulose hydrogels with high response sensitivity and mechanical adaptability for flexible strain sensor and triboelectric nanogenerator

Cellulose hydrogels are widely regarded as green and environmentally friendly flexible electronic materials. Herein, a novel multiple cross-linked cellulose hydrogel (MCC/SA20/MCC-g-P(AA-co-AM-AMPS)) with high sensitivity (gauge factor = 440, 670 %, 60 ms) and good mechanical adaptability was designed and prepared. The prepolymer (MCC-g-P(AA-co-AM-AMPS)) was introduced into the microcrystalline cellulose/sodium alginate (MCC/SA) hydrogel network to form a multiple cross-linked network structure, which effectively enhanced the tension and elasticity of the cross-linked network, and improved the mechanical adaptability and sensitivity of the hydrogel. Additionally, it was assembled as a strain sensor that can accurately identify and monitor various motion states of the human body. It was also assembled as a friction nanogenerator (TENG) that continuously generates a stable open circuit voltage (7.2 V) for self-powering small electronic devices. This study provides an effective and feasible strategy for cellulose hydrogels in flexible sensors for sports health monitoring, sustainable green energy harvesting, and self-powering applications for small electronic devices.

Transferring Data Using a Visible Light

This project aims to demonstrate the availability and usability of a basic Li-Fi system that can be manufactured and utilised in daily life starting with the fundamental tools. We present a novel method of data transfer that combines sustainable energy harvesting with high-speed communication (using Li-Fi technology). This makes it suitable for a range of applications, such as secure data communication, Internet of Things (IoT) devices, and wireless sensor networks. A light communication system called Li-Fi uses modulating circuits and regular LED bulbs. We shall explain in this how light from an LED diode is utilised as a transmission medium for this purpose. Compared to Wi-Fi, it transfers data more quickly. In the experimental setup, modulated light signals are emitted by LEDs and detected by solar cells that have photodetectors installed. To recover the transmitted data, the receiving signal must be decoded. Light from the source is directed through a plane convex lens to minimise losses at the lowest levels. If the light source is precisely at the focal point, the light rays on the exit will extend nearly parallel and strike the solar cell with the least amount of loss. It also emphasises how this technology will be used in the future. Additionally, it showcases the technology that will enable data transfer at the speed of light in the future and make efficient use of the light spectrum to connect gadgets to the internet. ex. Organization v2v(vehicle-to-vehicle), Smart mirror, Indoor navigation in building and landscapes, Hospital and health care...etc.,

2D Semiconductor Nanostructures for Solar‐Driven Photocatalysis: Unveiling Challenges and Prospects in Air Purification, Sustainable Energy Harvesting, and Water Treatment

AbstractThe use of solar light to accelerate chemical processes (photocatalysis) has the potential to alleviate the pollution and energy crises. Thanks to their large surface area, unusual electronic structure, and abundance of low‐coordinate surface atoms, 2D semiconductors have shown enormous promise in photocatalytic applications. The synthesis, photoexcitation processes, design, and development of 2D semiconductor photocatalysts are thoroughly examined in this perspective, as well as their possible applications in air purification, solar energy conversion, organic synthesis, carbon capture and storage, and water treatment. This work highlights ongoing research efforts focused on improving the selectivity and efficiency of photocatalytic applications based on 2D semiconductors by means of hybrid systems, heterostructures, doping, and computational methodologies, together with open challenges. Finally, the integration of 2D semiconductor photocatalysts into indoor and outdoor environments is discussed, thereby facilitating the purification of air and water and generating clean energy, which assists in the pursuit of sustainable development objectives.

Extraordinary-durable cylindrical rotary triboelectric nanogenerator based on CB/Fe3O4/PDMS microarrays for energy harvester

Triboelectric nanogenerators (TENGs) with exceptionally durable energy harvesting performance are increasingly important in the pursuit of sustainable/renewable energy sources. However, the durability of frictional electricity material inevitably decreases due to material abrasion, which significantly hinders their real-world application. Here, robust and flexible films composed of CB/Fe3O4/PDMS and CB/Fe3O4/PDMS@Au microarrays have been employed as paired frictional electricity materials, wrapped around the surface of cylindrical electrodes to develop rotary TENG. When two rotary electrodes contact, the aforementioned paired microarrays intersect, causing overlapping friction. This leads to an increased contact electrified surface area, resulting in high output performance with a maximum peak power density reaching 16.2 mW m−2. Importantly, the configuration of this rotary TENG described herein effectively prevents frictional material damage caused by friction. This is achieved by allowing free rolling movement instead of being fixed in a stationary position, thereby ensuring exceptional durability. Furthermore, the resulting rotary TENG shows exceptional biomechanical energy harvesting capability even after undergoing multiple rotations and experiencing friction for up to 100,000 cycles. The durable PDMS-based microarrays film exhibits great potential for flexible/wearable TENGs, highlighting their potential applications and impact on the field of sustainable energy harvesting technology.

Enhancing the piezoelectric performance of composite PVDF flexible films through optimizing β phase content, investigating additive effects, step‐wise polarization, and thermal pressing time for energy harvesting applications

AbstractPolyvinylidene fluoride (PVDF), known for its piezoelectric versatility, emerges as a key contender for advancing efficient and sustainable energy harvesting in nanogenerators. This study explores the potential enhancement of piezoelectric properties in flexible PVDF polymers, employing a comprehensive approach through the solution casting method. The investigation integrates diverse additives, thermal treatments, and polarization methods to optimize performance, focusing on the impact of the β phase transition on electrical voltage generation. Utilizing the Taguchi experimental design, the study identifies optimal conditions for the composite PVDF film (OPT‐PVDF) through FT‐IR, XRD, and DSC analyses, with output voltage measurements confirming superior performance compared to pure PVDF (P‐PVDF). Specifically, BN‐doped PVDF films, with an 80% β phase content, achieve an impressive 6.48 V output voltage. This research underscores PVDF's potential for energy harvesting, emphasizing the pivotal role of optimizing β phase content, additive strategies, and the effects of polarization and thermal treatments. The study further evaluates the effect and necessity of subsequent thermal treatment and step‐wise polarization effects on the composite PVDF film material. The findings indicate that BN‐doped composite PVDF films, produced under optimal conditions, exhibit advanced piezoelectric properties.

Self-powered water-splitting using triboelectric nano-generators for green hydrogen production: Recent advancements and perspective

The discovery of triboelectric nano-generators (TENGs) has resulted in the invention and development of self-powered electronics and devices. TENGs offer numerous benefits including their portability, affordability, and sustainable micro-scale energy harvesting in the realm of self-powered sensors and portable devices. TENGs have the capability to function as an autonomous power source. Integration of TENG with electrochemical processes can facilitate self-powered electrochemistry such as water splitting (or electrolysis) for H2 production, thereby eliminating the requirement for an external power supply. This review primarily centers on the operation and the recent advancements of TENGs in self-powered water-splitting for clean and environment-friendly H2 production utilizing renewable energy sources including wind, wave, and low-scale mechanical energy. The concept of conducting water-splitting without reliance on an external power source holds the potential for significant use in the field of clean and green H2 production with cost advantages, sustainability, and other environmental benefits.

Exploring the role of ZnS as passivation layer on SrTiO3/Bi2S3 heterojunction photoanode for improved solar water splitting

Sustainable energy harvesting has emerged as a frontier research area and relentless efforts are being put in to tackle the tenacious issues of global warming and energy crisis. Photoelectrochemical (PEC) water splitting is regarded as a promising technology to produce H2. In this study, we report facile fabrication of ZnS modified SrTiO3/Bi2S3 (STO) heterojunction photoanode for PEC water splitting. Ternary heterojunction photoanode was fabricated using sol-gel followed by SILAR methods. Coupling of wide band gap STO with narrow band gap Bi2S3 photosensitizer extends the absorption edge while the ZnS passivation layer improves electrode stability by preventing direct contact of Bi2S3 with electrolyte and providing an active energy state for facile charge transfer to improve charge separation. Decreased rate of recombination and elongated lifetime of photogenerated charge carriers resulted in enhanced charge carrier dynamics. STO/Bi2S3/ZnS photoanodes displayed a photocurrent density (J) of 1.89 mA.cm−2 at 1.23 V vs RHE and HC-STH of 1.19% at 0.42 V vs RHE in neutral medium while the corresponding values in basic medium were J = 5.08 mA cm−2 at 1.23 V RHE and HC-STH 4.8% at 0.71 V vs RHE; considerably higher than bare STO and binary STO/Bi2S3 electrodes. The superior performance in basic medium could be attributed to the presence of hole scavengers. The improved photostability >3000 s was attributed to ZnS deposition. To better under the role of hole scavengers the quantification of O2 and H2 was undertaken.

Emerging pathways in thermoelectric: Chemical bath deposition of magnesium selenide thin films for sustainable energy harvesting

In this study, magnesium Selenide (MgSe) thin films were synthesized on glass substrate using the chemical bath deposition (CBD) method for thermoelectric power generation. After cleaning of glass substrate, selenium powder was dissolved in nitric acid to produce SeO2 and magnesium chloride was then introduced as the source of magnesium. Both SeO2 and MgCl2 were dissolved in 100 ml of dI water and later, these solutions were unified gradually. After that, the cleaned glass substrates were placed in the solution, while keeping the reaction temperature constant at 50o C for the deposition durations of 24, 48, 72, and 96 h. A number of characterization techniques, namely X-ray Diffraction (XRD), Raman spectroscopy and Scanning Electron Microscopy (SEM) were performed for structural and surface analysis of grown thin films. The effect of deposition time duration on the thermoelectric properties was investigated in depth using the Seebeck and Hall systems. It was found that the values of the Seebeck coefficient and power factor obey the increasing trend with maximum values 196.93 μV/K and 21.5 × 10−8 W/mK2 respectively. These observed values are seems to be the highest values for magnesium selenide thin film ever reported in the literature according to the best of our knowledge. Therefore, we have concluded that MgSe thin films supposed to be emerging material for thermoelectric power generation applications.

Enhanced light-responsive supercapacitor utilizing BiVO4 and date leaves-derived carbon: A leap towards sustainable energy harvesting and storage

This study explores light-responsive supercapacitors, aiming to transform energy systems by enabling the simultaneous conversion and storage of light into electricity. The study introduces an innovative light-responsive supercapacitor, employing bismuth vanadate (BiVO4) as the photoactive material and date leaf-derived carbon (DLC) as the conductive electrode material. The device also incorporates fluorine-doped tin oxide (FTO) as the transparent current collector and Na2SO4 as the electrolyte. The constructed FTO/BiVO4/DLC//DLC/FTO asymmetric light-responsive supercapacitor showcased remarkable electrochemical performance, achieving a capacitance of ∼150 F/g at a current density of 0.5 A/g, thereby validating its effective charge transfer capacity during electrical activities. Further experimentation with varying photo-charging times resulted in a peak specific capacitance of ∼290 F/g. The device demonstrated an energy density of around ∼13 Wh/kg and a power density of ∼200 W/kg in the absence of light, with the energy density notably doubling to 26 Wh/kg upon extended photo-charging. Remarkably, the supercapacitor maintained ∼90% of its initial specific capacitance and ∼86% of its Coulombic efficiency following 12000 GCD cycles, underscoring its electrochemical stability and durability. The development of such a proficient and resilient light-responsive supercapacitor holds significant promise for the advancement of the energy-storage sector and offers valuable insights for renewable energy researchers.

Semiconductor–Semimetal Composite Engineering Enabling Record‐High Thermoelectric Power Density for Low‐Temperature Energy Harvesting

AbstractSustained thermoelectric efforts have concentrated on the enhancement of conversion efficiency of power generators, while simultaneously achieving high output power continues to lag. Specifically, the highest output power density of emerging Mg‐based modules reported so far is only half of that of commercial Bi2Te3‐based, mainly due to the low power factor of MgAgSb. Herein, homogenously distributed MgCuSb in situ nanoprecipitates in the MgAgSb matrix effectively optimized carrier concentration due to the effect of carrier injection from the metal–semiconductor Ohmic contact. As a result, a record‐high average power factor of 27.2 µW cm−1 K−2 is obtained in MgCu0.1Ag0.87Sb0.99 composite within the temperature range of 300–550 K, which is much higher than ever reported values of MgAgSb system. Benefiting from the combination of the optimized average power factor of p‐leg and low interface resistivity, a fabricated eight‐pair MgCu0.1Ag0.87Sb0.99/Mg3.2Bi1.5Sb0.5 module demonstrates an unprecedently high output power density of 2.9 W cm−2 under a temperature difference of 300 K, outperforming all low‐temperature advanced thermoelectric modules. Meanwhile, a competitive conversion efficiency of 7.65% is obtained simultaneously. The work significantly advances high‐power thermoelectric applications of Mg‐based modules in the field of low‐temperature sustainable energy harvesting.

Roly-poly inspired tribo-electromagnetic energy harvester toward sustainable ocean energy harvesting

With the increasing global population, the demand for energy has also risen significantly. However, the utilization of fossil fuels for the purpose of energy production has resulted in the release of carbon emissions, accelerating the global warming. Therefore, the demand for carbon-free and renewable energy sources, which can replace the fossil fuels, is growing. In this study, a roly-poly-structure-inspired hybridized energy generator (RPHG) is demonstrated by combining a roly-poly triboelectric nanogenerator with an electromagnetic generator. By utilizing the RPHG, multiple vibrations can be induced from an external force due to the recovering force originated by the roly-poly structure of the RPHG. Consequently, the RPHG is capable of harvesting multiple vibrations from a single input vibration. To optimize the electrical performance of the RPHG, the effects of the substrate shape and the number of polytetrafluoroethylene balls into the electrical output is investigated. Also, the effect of the center of gravity on the electrical output generated from the RPHG is theoretically and experimentally confirmed. As a result, the average vibration number is increased from 2.6 to 25.1 with the 20 polytetrafluoroethylene balls when the tilted substrate with a tilted angle of 170° is applied to the RPHG, compared to the electrical output is generated from the RPHG with a flat substrate. The synergistic effect of the hybridization is demonstrated by comparing the charging speeds of a capacitor and the RPHG shows the fastest speed for charging the capacitor. Furthermore, our RPHG generates 2.45 and 19.29 times higher electrical output than the roly-poly triboelectric nanogenerator (RP-TENG) and electromagnetic generator, respectively. The proposed RPHG demonstrates the 195% higher conversion efficiency in terms of energy compared to the power owing to its unique structure. Also, although the RP-TENG and TENG without roly-poly structure (NRP-TENG) generate similar electrical power, the RP-TENG generates 242% higher electrical energy than NRP-TENG, showing the great potential to harvest the mechanical energy due to the roly-poly structure. As an application, a self-powered ocean wave monitoring system is implemented using the RPHG and it successfully detects strong, calm, and gentle waves. These results show the great potential of the RPHG to harvest vibration and ocean wave energy. Hence, we expect our RPHG to be a promising energy-harvesting solution for generating carbon-free energy.

Low-dimensional halide perovskite/PVDF nanocomposite with enhanced piezoelectricity as flexible biomechanical energy harvester

Sustainable energy harvesting is the need of the hour, and piezoelectric nanogenerators (PENG) offer tremendous opportunities in this field. We have investigated the mechanical energy harvesting applications of a nanocomposite comprising a low-dimensional halide perovskite (HP) and polyvinylidene fluoride (PVDF). Cs4PbBr6 HP was prepared using mechanochemical synthesis, and a composite film of PVDF with Cs4PbBr6 was utilized as the PENG to scavenge energy from day-to-day human biomechanical activities. The properties and output results of the fabricated devices with changing weight percentages (wt.%) of HP used as nanofillers in the PVDF matrix are compared to those of a pure PVDF. A 6 wt.% concentration of Cs4PbBr6 induces the composite's electroactive β-phase to around 87%. The polarization hysteresis (P-E) loop measurement reveals a remanent polarization of 0.31 µC/cm2. The measured piezoelectric coefficient (d33) is about ⁓12 pm/V, and the piezoelectric amplitude is ∼500 pm for the optimized PENG at the maximum applied bias of ±30 V. The device shows an instantaneous output voltage of ⁓90 V, a current of ⁓3.8 μA, and power of ⁓80 µW across a 5 MΩ resistor. Simple daily human activities like finger tapping, leg-toe pressing, finger bending, heel pressing, and walking are used to generate output voltages using PENG with prospective usage in powering portable electronic devices. The output AC voltage of the device is employed to charge a 10 µF capacitor up to ∼3.5 V and shows exceptional stability over long cycles. The output power generated is adequate for lighting commercial LEDs without any external input. The Cs4PbBr6/PVDF composite films thus demonstrate significant potential to be deployed as high-performance, portable, and wearable mechanical energy harvesting devices.

Design and development of a horizontal contact separated (HCS) test setup for measuring the performance of triboelectric nanogenerator for sustainable energy harvesting applications.

Triboelectric nanogenerators (TENGs) can play a pivotal role in harnessing non-utilized reciprocating motion and convert it into electrical energy that can later be stored in a battery or capacitor to power various Internet of Things-based smart electronic and wearable devices. Herein, we designed a cost-effective instrumental test bed focused on investigating the output performance of a horizontal contact separation mode triboelectric nanogenerator by varying the input parameters, such as applied force, motor speed, triboplate separation, and frequency of instrumental setup. The test bed mainly consists of three major parts: (i) application of force, (ii) tapping of TENG sample, and (iii) output parameters measurement. The output performance in terms of open circuit output voltage (VOC), short circuit current (ISC), and power density of polydimethylsiloxane-based TENG was monitored and optimized by varying the input parameters. A low-cost current measuring circuitry using an operational amplifier integrated circuit has been proposed with 92% accuracy. The maximum value of VOC and ISC was observed to be 254V and 31.8 µA at a motor speed of 600rpm, the distance between both the plates was 6mm, the input applied force of 40 N, and the striking frequency of 3Hz. The maximum power density of 2.1 W/m2 was obtained at an input impedance of 8 kΩ. The durability of the test bed as well as the TENG sample was also measured for 25h. The degree of uncertainty was measured for VOC, ISC, and applied force and calculated to be 1.62%, 7.45%, and 6.27%, respectively.

Sustainable energy harvesting and breath sensing with electrospun triboelectric nylon-6

A high-performance triboelectric nanogenerator (TENG) has been developed for breath sensing applications, utilizing tribopositive electrospun nylon-6 nanofibers and tribonegative fluorinated ethylene propylene (FEP). The optimization toward the development of electrospun nylon-6-based TENG includes a range of factors such as the applied force and frequency on tribo responses, the thickness of the fiber mat, the concentration of nylon-6 in the fiber mats, and the selection of the tribonegative material for pairing with nylon-6 nanofiber. Among these parameters, the nanofiber prepared with 18 wt% nylon-6, characterized by a uniform fiber distribution, the highest surface area of 55.69 m2 g−1, and an optimal thickness of 0.169 mm, demonstrated excellent TENG performance, among others. The TENG module constructed using nanofiber in a 4 cm2 area showed the TENG responses of more than 30 μA short-circuit current, 200 V open-circuit voltage, and 90 nC charge when hand-pressed. It achieved a substantial power density of 890 mW m−2 at 20 MΩ by applying a constant force of 10 N at a 10 Hz frequency. Charging a 1 μF capacitor to approximately 30.1 V in just 30 s highlights the potential of electrospun nylon-6 as a promising material for nanogenerator energy harvesting and sensing applications. The TENG device was found to be sufficient to power small, portable electronics such as LEDs and digital watch displays. A wearable belt was fabricated to showcase its breath-sensing capabilities by pairing it with FEP. The microcontroller connected to the TENG in the wearable belt is used to analyze the output produced through breathing patterns, subsequently activating a buzzer and LED by the nature of the breathing.

Synergistic effects of rGO functionalization in nanocomposite-based triboelectric nanogenerators for enhanced energy harvesting

Enhancing the performance of triboelectric nanogenerators (TENGs) by integrating advanced energy materials is crucial for broadening their applications. In this study, the tribo-positivity of polyvinyl alcohol (PVA) is physically tailored by doping with functionalized reduced graphene oxide (FrGO) into the polymer matrix, aiming to design high-performance TENGs. The pristine PVA and -OH, -COOH, and -NH2 FrGO nanocomposite with varying filler quantities (0–2 wt/wt%) are subjected to various characterizations for elucidating structural, surface and electrical properties. Further, electrical measurements of as-fabricated FrGO-TENGs revealed a notable increase in both voltage and current with increasing filler quantities. Interestingly, the NH2 FrGO-TENG shows maximum electrical output compared to –OH and –COOH FrGO-TENGs. Also, the open-circuit voltage (VOC) and short-circuit current (ISC) of NH2 FrGO-TENG are about 10 and 17 times more than that of pristine PVA-TENG. This substantial improvement is attributed to the extensive hydrogen bonding between the PVA-NH2 FrGO. Furthermore, the practical utility of the optimized device is demonstrated by showcasing its ability to power LEDs, digital timers, and commercial capacitors through a rectifier bridge. Thus, the results proved the potential of incorporating -NH2 FrGO into PVA as a synergistic material for sustainable and improvised energy harvesting, owing to opening new avenues for self-powered applications.

The future of tire energy: a novel one-end cap structure for sustainable energy harvesting

AbstractPiezoelectric energy harvesting is gaining popularity as an eco-friendly solution to harvest energy from tire deformation for tire condition monitoring systems in vehicles. Traditional piezoelectric harvesters, such as cymbal and bridge structures, cannot be used inside tires due to their design limitations. The wider adoption of renewable energy sources into the energy system is increasing rapidly, reflecting a global attraction toward the utilization of sustainable power sources (Aljendy et al. in Int J Power Energy Convers 12(4): 314–337, 2021; Yesner et al. in Evaluation of a novel piezoelectric bridge transducer. In: 2017 Joint IEEE International Symposium on the Applications of Ferroelectric (ISAF)/International Workshop on Acoustic Transduction Materials and Devices (IWATMD)/Piezoresponse Force Microscopy (PFM). IEEE, 2017). The growing interest in capturing energy from tire deformation for Tire Pressure Monitoring Systems (TPMS) aligns with this trend, providing a promising and self-sustaining alternative to traditional battery-powered systems. This study presents a novel one-end cap tire strain piezoelectric energy harvester (TSPEH) that can be used efficiently and reliably inside a tire. The interaction between the tire and energy harvester was analyzed using a decoupled modeling approach, which showed that stress concentration occurred along the edge of the end cap. The TSPEH generated a maximum voltage of 768 V under 2 MPa of load, resulting in an energy output of 32.645 J/rev under 1 MPa. The computational findings of this study were consistent with previous experimental investigations, confirming the reliability of the numerical simulations. The results suggest that the one-end cap structure can be an effective energy harvester inside vehicle tires, providing a valuable solution for utilizing one-end cap structures in high-deformation environments such as vehicle tires.

Terminalia Chebula Fruits Powder as Tribopositive Material for High‐Performance Triboelectric Nanogenerator

Triboelectric nanogenerator (TENG) has generated a lot of attention for developing self‐powered/battery‐free technology. These kinds of energy harvesting devices are required for a sustainable future. In this work, the TENG is developed by using the Terminalia Chebula (T. Chebula) biomaterial as tribopositive material. The physiochemical characterizations suggest that T. Chebula has hydroxyl and carbonyl groups which are important to get tribopositivity from the material. The T. Chebula tribopositive material has been tested for the TENG with different electronegative layers such as polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and polydimethylsiloxane (PDMS). The T. Chebula/PTFE device exhibited a higher output performance. This pair was used for the area and frequency‐dependent studies. In the present case, 16 cm2 device area and 5 Hz frequency conditions show outstanding device performance. Furthermore, the device has been employed for operating low‐power electronic devices such as LEDs and a calculator which operated without any degradation. These results suggested that T. Chebula is a potential tribopositive material for sustainable energy harvesting technology.

A Novel Multifunctional Photonic Film for Colored Passive Daytime Radiative Cooling and Energy Harvesting.

Passive daytime radiative cooling (PDRC) materials with sustainable energy harvesting capability is critical to concurrently reduce traditional cooling energy utilized for thermal comfort and transfer natural clean energies into electricity. Herein, a versatile photonic film (Ecoflex@BTO@UAFL) based on a novel fluorescent luminescence color passive radiative cooling with triboelectric and piezoelectric effect is developed by filling the dielectric BaTiO3 (BTO) nanoparticles and ultraviolet absorption fluorescent luminescence (UAFL) powder into the elastic Ecoflex matrix. Test results demonstrate that the Ecoflex@BTO@UAFL photonic film exhibits a maximum passive radiative cooling effect of ∽10.1 °C in the daytime. Meanwhile, its average temperature drop in the daytime is ~4.48 °C, which is 0.91 °C higher than that of the Ecoflex@BTO photonic film (3.56 °C) due to the addition of UAFL material. Owing to the high dielectric constant and piezoelectric effect of BTO nanoparticles, the maximum power density (0.53Wm-2 , 1Hz @ 10 N) of the Ecoflex@BTO photonic film-based hybrid nanogenerator is promoted by 70.9% compared to the Ecoflex film-based TENG. This work provides an ingenious strategy for combining PDRC effects with triboelectric and piezoelectric properties, which can spontaneously achieve thermal comfort and energy conservation, offering a new insight into multifunctional energy saving.