Green Energy Harvesting Research Articles

Unlocking the Rhythmic Power of Bacterial Cellulose: A Comprehensive Review on Green Energy Harvesting and Sustainable Applications

AbstractBacterial cellulose is a biodegradable and ecologically safe material that has the potential to convert mechanical vibrations into electrical energy. This review introduces green energy harvesting, a novel concept that harnesses natural processes to provide sustainable energy. A thorough overview of bacterial cellulose, covering its distinctive features, its biological origin, and its energy conversion process, is fully presented. The different materials and methods used to design and fabricate bacterial cellulose‐based energy harvesters are explored. Moreover, the various applications and benefits of these devices in the context of renewable energy are examined. The current challenges and limitations of this emerging field are identified and the possible avenues for future research are suggested. The significance of adopting eco‐friendly approaches in achieving a balance between human needs and environmental preservation is highlighted. By providing a comprehensive and critical assessment of bacterial cellulose as a green energy harvester, this review aims to motivate researchers, engineers, and policymakers to tap into the rhythmic potential of this natural material in building a more sustainable and resilient future.

Enhanced performance of TENG through graphene oxide and transition layer coupling: Achieving green energy harvesting and powering wearable devices

Triboelectric nanogenerators (TENGs) offer a novel approach to harvesting green energy due to their simple structure, low manufacturing cost, and suitability for collecting low-frequency mechanical energy. Previous research has primarily focused on the impact of single factors on the electrical output of TENGs, such as the generation, storage, or loss of triboelectric charges. In this study, we enhanced the generation of triboelectric charges by introducing graphene oxide (GO) and reduced charge loss through a Polyimide (PI) film as a transition layer. By combining both, we maximized the electrical output performance of the TENG. The ISC, VOC and charge of the optimized TL-TENG are 33.23 μA, 318.52 V and 152.03 nC, respectively, with a maximum output power of 2.6 W/m2. The results indicate that the performance enhancement from the transition layer exceeded that of GO alone, possibly because it reduced the electron drift rate by 97.37 %. Additionally, the TL-TENG demonstrated excellent mechanical durability, with ISC decrease of only 2.25 % after 5×104 contact-separation cycles. The device also showed effective metal anti-corrosion properties and could harvest energy from mechanical vibrations and human motion, powering at least 107 LEDs and supporting small electronic devices such as digital watches. The outcomes of this study hold promise for providing reliable energy sources for wearable devices and offer theoretical guidance for designing high performance TENGs.

Synergistic photocatalytic breakdown of azo dyes coupled with H2 generation via Cr-doped α-Fe2O3 nanoparticles

This research addresses the scalable and inexpensive synthesis of α-Fe2O3via hydrothermal method without any precipitating agent as well as the enhancement of solar driven photocatalytic and H2 production through doping different chromium proportions. Competency of α-Fe2O3, both pure and doped with chromium, to function as photocatalyst was evaluated by its interaction with multiple dyes, which was real-time monitored utilizing (Internet of Things) IoT technique. By adding chromium, the rate of deterioration increased substantially from 15 to 94% for TB under sunlight in a remarkably brief 20 min by employing a very small amount of Cr0.8Fe1.2O3 (0.3 g/L), as evidenced by high degree of mineralization i.e. 85% and LC-HRMS. Also, the rapid breakdown of Trypan Blue (TB) was indicated by BOD5/COD ratio. Moreover, Cr-doped α-Fe2O3 displays excellent H2 production (~ 132 μmol h−1 g−1) as compared to α-Fe2O3. This work highlights the potential utilization of Cr-doped α-Fe2O3 for the purification of industrial waste water and green energy harvesting.

A wide voltage range non‐isolated continuous input buck‐boost converter for optimal green energy harvesting in LED lighting systems

A wide voltage range non‐isolated continuous input buck‐boost converter for optimal green energy harvesting in LED lighting systems

Nb-based copper sulvanites for potential green energy harvesting under induced isotropic pressure

This work explores the mechanical, electronic, dynamical stability, optical, and thermoelectric properties of Nb-based copper sulvanite compounds Cu3NbX4 (X=S, Se, Te) at 0, 5, 10, 15, and 20 GPa isotropic pressure within the framework of density functional theory (DFT). Calculated results are found in good agreement with experimental data, specifically in the values of their lattice parameters and optical band gaps. Cu3NbX4 exhibits promising optical properties for photovoltaic applications with enhanced properties under pressure. Exploration on transport properties also shows moderate thermoelectric figure of merit with slight improvement under pressure.

Nanocellulose and multi-walled carbon nanotubes reinforced polyacrylamide/sodium alginate conductive hydrogel as flexible sensor

Conductive hydrogels have been widely applied in human–computer interaction, tactile sensing, and sustainable green energy harvesting. Herein, a double cross-linked network composite hydrogel (MWCNTs/CNWs/PAM/SA) by constructing dual enhancers acting together with PAM/SA was constructed. By systematically optimizing the compositions, the hydrogel displayed features advantages of good mechanical adaptability, high conductivity sensitivity (GF = 5.65, 53 ms), low hysteresis (<11 %), and shape memory of water molecules and temperature. The nanocellulose crystals (CNWs) were bent and entangled with the backbone of the polyacrylamide/ sodium alginate (PAM/SA) hydrogel network, which effectively transferred the external mechanical forces to the entire physical and chemical cross-linking domains. Multi-walled carbon nanotubes (MWCNTs) were filled into the cross-linking network of the hydrogel to enhance the conductivity of the hydrogel effectively. Notably, hydrogels are designed as flexible tactile sensors that can accurately recognize and monitor electrical signals from different gesture movements and temperature changes. It was also assembled as a friction nanogenerator (TENG) that continuously generates a stable open circuit voltage (28 V) for self-powered small electronic devices. This research provides a new prospect for designing nanocellulose and MWCNTs reinforced conductive hydrogels via a facile method.

Probing the Structural, Electronic, Thermodynamic, Optical, and thermoelectric features of Lead-Free double perovskites Na2ScAgZ6 (Z=Br, I) for green energy harvesting

In this study,weemployed density-functional theory (DFT) to investigate the structural, electrical, thermodynamic, optical, and thermoelectric characteristics ofNa2ScAgZ6 (Z=Br, I). The Goldschmidt tolerance factor (τ), formation energy, and Gibbs free energy values reveal a high level of thermodynamic and structural stability. Additionally, the thermodynamic stability of the explored double perovskites Na2ScAgZ6 (Z=Br, I) has been verified by employing ab initio finite temperature molecular dynamicssimulation. An indirect bandgap of 2.01 eV (Na2ScAgBr6)and 0.95 eV (Na2ScAgI6)is found using TB-mBJ approximation. This is an essential parameterfor photovoltaic applications. The bandgap values of thesecompounds show that they absorb the majority of radiation in the visible region; thereby substituting bromide withiodidecauses a decrease inthe bandgap. The current investigation aims to study the absorption of light energy, polarization, refractive index, and energyloss across the energy rangesfrom 0 to 6 eV. The dielectric constant has been looked at to identify the highest absorption of incident light in the visible area. The optical characteristics are suitable for use in photovoltaic appliances as the absorption takes place in the visible range. Using the BoltzTraP code, the thermoelectric properties are evaluated and found that the highest ZT values are 0.78 (Na2ScAgBr6)and 0.92 (Na2ScAgI6), respectively. This indicates that these materials can be viable alternatives for photovoltaic and thermoelectric devices.

Revealing the Structural, Electronic, Optical, and Thermoelectric Aspects of the Gold‐Based Double Perovskites X2Au+Au3+Br6 (X = Cs, Rb) Using a First‐Principles Approach

Lead‐free double perovskites are now assumed to be suitable candidates for green energy harvesting in particular as active materials for solar cells and thermoelectric generators, which can meet future generation energy needs. Therefore, we explore the Au‐based halide double perovskites X2Au+Au3+Br6 (X = Cs, Rb) from the first principles approach. Density functional theory (DFT) is utilized to explore the electronic structure with DFT code Quantum ESPRESSO. The mechanical, thermodynamic, and structural stability is ensured from Burn‐Haun criterion, formation energies, and Goldschmidt factors, respectively. The examined materials have stable structures with direct band gaps i.e. 1.54 and 1.72 eV. The existence of band gaps in the visible region motivates us to explore the optical properties, which give fascinating outcomes. The absorption coefficients and optical conductivity peaks are found to be significant in the visible region i.e., ≈104 cm−1 and ≈1015 s−1, respectively. Additionally, the thermoelectric properties are also investigated using Boltzmann transport theory. There are several good gestures for the usage in the thermoelectric generators since the values of Seebeck coefficients (446.5, and 225.2 μV K−1), power factors (1.75 × 1011 W mk−2 s, and 1.24 × 1011 W mk−2 s), and figure of merits (0.92 and 0.73) are noteworthy for Cs2AuAuBr6 and Rb2AuAuBr6, respectively, at room temperature T = 300 K.

Ultra-stable, lightweight and superelastic waste flax-based aerogel for multifunctional applications

Multifunctional aerogels constructed from natural waste biomass have attracted great attention in the fields of green energy harvesting, flexible wearable sensing and natural environment restoration. However, the complex and polluted extraction of natural materials and the poor mechanical property have seriously hindered the development of natural material-based aerogels. Hence, a novel aerogel with capabilities of high-elasticity, stabilized constructions and weightlessness was prepared via waste flax staple fibers (simply physically disrupting) and multi-walled carbon tubes. Due to the assistance of cross-linking agent and carbon tubes, the aerogel was endowed with multiple properties including high photothermal conversion (97.2 %), superstability at the wide range of 0–29 KPa and outstanding compression resilience at different strains (up to 60 % and 100 cycles). Consequently, it is promising that the fabricated aerogel may be as a piezoresistive sensor to monitor different locations of the body for continuous detection of motor behavior. Further, the sample was also utilized as an evaporator with excellent water evaporation effect (1.93 kg·m−2·h−1) under 1 sun and to efficiently purify various types of wastewater for obtaining pure water. This multi-purpose aerogels prepared in this work display admirable potential for efficient environmental purification, advanced smart materials and green energy harvesting.

Rationally Improved Surface Charge Density of Triboelectric Nanogenerator with TiO2-MXene/Polystyrene Nanofiber Charge Trapping Layer for Biomechanical Sensing and Wound Healing Application.

Triboelectric nanogenerators (TENGs) have become reliable green energy harvesters by converting biomechanical motions into electricity. However, the inevitable charge leakage and poor electric field (EF) of conventional TENG result in inferior tribo-charge density on the active layer. In this paper, TiO2-MXene incorporated polystyrene (PS) nanofiber membrane (PTMx NFM) charge trapping interlayer is introduced into single electrode mode TENG (S-TENG) to prevent electron loss at the electrode interface. Surprisingly, this charge-trapping mechanism augments the surface charge density and electric output performance of TENGs. Polyvinylidene difluoride (PVDF) mixed polyurethane (PU) NFM is used as tribo-active layer, which improves the crystallinity and mechanical property of PVDF to prevent delamination during long cycle tests. Herein, the effect of this double-layer capacitive model is explained experimentally and theoretically. With optimization of the PTMx interlayer thickness, S-TENG exhibits a maximum open-circuit voltage of (280V), short-circuit current of (20µA) transfer charge of (120 nC), and power density of (25.2 µW cm-2). Then, this energy is utilized to charge electrical appliances. In addition, the influence of AC/DC EF simulation in wound healing management (vitro L929 cell migration, vivo tissue regeneration) is also investigated by changing the polarity of trans-epithelial potential (TEP) distribution in the wounded area.

Probing the structural, magneto-electronic, thermophysical, and thermoelectric properties of vanadium-based V2MnZ (Z = As, Ga) Heusler alloy: a computational assessment

The structural, magneto-electronic, thermophysical and thermoelectric properties of vanadium-based V2MnZ (Z = As, Ga) alloys have been investigated using density functional theory simulation scheme and semiclassical Boltzmann transport methods. First of all, the structural characterization has been performed in ferromagnetic and non-magnetic states which signifies that both the alloys crystallized in C1b type structure with space group F-43m. We also computed the various thermodynamical parameters such as heat capacity (Cv), Debye temperature (θ D), and grüneisen parameter (γ) of these materials, with the help of quasi-harmonic approximation (QHA) at pressures ranging from 0 to 20 GPa and temperatures ranging from 0 to 900 K. We have used the Boltzmann transport theory with the constant relaxation approximation as a basis for calculating various thermoelectric coefficients such as the Seebeck coefficient, power factor, total thermal conductivity and figure of merit. The efficient half-metallicity and thermoelectric responses contribute to spintronics and green energy harvesting technology.

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.

Boosting the triboelectric performances of biowaste chitosan keratin triboelectric nanogenerator using carbon composite film as charge storage and charge recombination blocking intermediate layer

Environmental conservation efforts are promoting energy-generation technologies that avoid the use of highly polluting fuels and promote the reuse of waste materials. Advances in triboelectric nanogenerators (TENGs) have led to the progress in harvesting energy from ambient mechanical sources and powering small devices and sensors while being compact, flexible, biocompatible, and eco-friendly. Nevertheless, the practical applications of TENG have limitations. Therefore, the development of TENG with excellent triboelectric performance, eco-friendliness, and low cost is crucial. Consequently, an environmentally friendly, inexpensive TENG device with outstanding triboelectric performance was designed using keratin-enhanced chitosan as a tribo-positive material, a carbon film as an intermediate layer, and polytetrafluoroethylene as a triboelectric negative material. The device was purposely designed to simultaneously play a role in waste treatment and efficient green energy harvesting. Therefore, keratin was extracted from recycled fur, and a carbon film was selected to enhance the triboelectric performance because of its excellent electrical conductivity and dielectric constant. The triboelectric properties of a chitosan keratin intermediate layer (CKI)-TENG were systematically investigated. Practical applications of the CKI-TENG in charging electronic devices and waste-noise harvesting were also studied. The developed CKI TENG exhibited outstanding triboelectric performance compared to a TENG device without an intermediate layer. Particularly, the charge transfer, output voltage, and power density was improved by 19%, 46%, and 60%, respectively, compared to the output of the chitosan-keratin (CK) TENG device. It also exhibited outstanding cyclic and charging-discharging stabilities. In addition, the power density of the developed CKI TENG was higher than that of previously reported TENG devices. Thus, it can play a significant role in green and clean energy generation and the utilization of the harvested energy in practical applications, such as biomedical sensors, charging electronic devices, smart textiles, and sensors.

Rational design of natural leather-based water evaporator for electricity generation and functional applications

In recent years, water evaporation-induced electricity has attracted a great deal of attention as an emerging green and renewable energy harvesting technology. Although abundant materials have been developed to fabricate hydrovoltaic devices, the limitations of high costs, inconvenient storage and transport, low environmental benefits, and unadaptable shape have restricted their wide applications. Here, an electricity generator driven by water evaporation has been engineered based on natural biomass leather with inherent properties of good moisture permeability, excellent wettability, physicochemical stability, flexibility, and biocompatibility. Including numerous nano/microchannels together with rich oxygen-bearing functional groups, the natural leather-based water evaporator, LeatherEmblic-NPs-SA/CB, could continuously produce electricity even staying outside, achieving a maximum output voltage of ∼3 V with six-series connection. Furthermore, the leather-based water evaporator has enormous potential for use as a flexible self-powered electronic floor and seawater demineralizer due to its sensitive pressure sensing ability as well as its excellent photothermal conversion efficiency (96.3%) and thus fast water evaporation rate (2.65 kg m−2 h−1). This work offers a new and functional material for the construction of hydrovoltaic devices to harvest the sustained green energy from water evaporation in arbitrary ambient environments, which shows great promise in their widespread applications.

A two-magnet energy harvesting device with buoy base for a marine terminal

It is crucial to explore new green energy sources to alleviate the earth’s energy depletion and the impact of air pollution and greenhouse effects. Although wafer manufacturing is increasing worldwide, the implementation of carbon footprint policies necessitates a shift toward green electricity. To expand the scale of wafer manufacturing, it is essential to develop terrestrial green electricity, which requires additional terrestrial green energy sources. This paper presents a green energy harvesting method that generates wave hydraulic energy via a vibration-based electromagnetic generator through a buoy. An energy harvester composed of two magnets in series driven by a buoy via a connected pole is introduced. The sensitivity of induced electricity to the energy harvester’s design parameters, including the magnets’ geometric dimensions (diameter and height), the coil’s turns, and layers, is analyzed. Additionally, the relationship between electricity and wave information (wave amplitude and wavelength) is explored. To evaluate the electrical power efficiency between a pair of single-magnet energy harvesters and the two-magnet harvester, a pair of parallel energy harvesters consisting of one magnet and paralleled in line is assessed. The impact of electricity on the horizontal span between the parallel energy harvesters is also investigated. To achieve maximal electricity, the two-magnet energy harvester is numerically optimized using a simulated annealing method. The numerical result shows that the two-magnet (in series) energy harvester can produce 0.472 W when the wavelength is 0.03, the amplitude is 0.09 m, and the wave speed is 3 m/s.

Green Energy Harvesting and Management Systems in Intelligent Buildings for Cost-Effective Operation

Nowadays, the rise of Internet of Things (IoT) devices is driving technological upgrades and transformations in the construction industry, the integration of IoT devices in buildings is crucial for both the buildings themselves and the intelligent cities. However, large-scale IoT devices increase energy consumption and bring higher operating costs to buildings. Therefore, harvesting the ambient cost-effective and clean energy sources is essential for the future development of intelligent buildings. In this work, we investigate the feasibility of integrating a typical triboelectric droplet energy harvester (DEH) into buildings. We demonstrate the energy harvesting capabilities of DEH on different sloped roof surfaces and complex curved building surfaces by simulating rainy weather with various rainfall intensities. The results indicate energy harvesting efficiency increases with larger tilt angles, which guides future smart architectural designs. This work is significant for the future integration of diversified, all-weather green energy collection and management systems, including raindrop energy, wind power generation, and solar energy, which will contribute to energy conservation and cost control in the next generation of smart buildings.

Energy harvester reliability study by Gaidai reliability method

AbstractThis study validates a novel structural reliability method, particularly suitable for high‐dimensional green energy harvesting device dynamic systems, versus a well‐established bivariate statistical method, known to accurately predict two‐dimensional system extreme response contours. Classic reliability methods dealing with time series do not always have an advantage of dealing easily with dynamic system high dimensionality, along with complex cross‐correlations among different system components. Energy harvesters constitute an important part of modern offshore green energy engineering; hence, proper experimental study along with safety and reliability analysis are of practical design and engineering importance. To study the performance of galloping energy harvesters, a series of laboratory wind tunnel tests have been conducted, selecting different wind speeds. This study illustrates the usage of the advocated novel reliability method, by analyzing bivariate statistics of experimental galloping energy harvester's dynamics. The bivariate statistics was extracted from available experimental results, more specifically for the device's voltage‐force dataset. Advantage of the proposed methodology being that relatively short experimental data record may still yield meaningful design results, provided proper statistical methods have been applied. Safety and reliability are important engineering concerns for all kinds of green energy devices. In the case of measured device's structural response, an accurate prediction of system failure or damage probability is possible, as illustrated in this study. Distinctive advantage of advocated novel semi‐analytical reliability methodology being the fact that it can tackle dynamic systems with practically unlimited number of dimensions (or components), along with complex nonlinear cross‐correlations between different system key components.

A fabric-based hydrovoltaic electricity generator with multi-component carbon black for sustainable energy output.

Water evaporation-induced electricity generators are considered a promising green energy-harvesting technology to alleviate the increasingly serious fossil energy crisis. Previous water evaporation-induced electricity generators mainly focused on single component carbon black, limiting the improvements in energy output. At present, there are relatively few studies on multi-component carbon black for improving electricity-generation performance. Herein, inspired by plant transpiration, we designed a fabric-based water evaporation-induced electricity generator (FWEG) based on multi-component carbon black, which can maintain a voltage of 0.65 V for more than 48 h. Through the synergistic effect of multi-component carbon black-enhanced oxygen-containing functional density, the FWEG can generate an enhanced output current of 61.61 μA without any additional energy input. Moreover, we show that the FWEG can be integrated readily to charge commercial capacitors or directly power LED lights and calculators for a long time. This work provides new insights for designing high-performance hydrovoltaic electricity generators for sustainable green energy harvesting.

Surface Functional Modification for Boosting Power Density of Hydrovoltaic Devices

AbstractGenerating electricity based on the interaction between water and materials is a new green energy harvesting technology. However, the performance based on streaming potential generation is not sufficient to drive microelectronic devices with high power supply demands. In this work, an asymmetric sandwich structure is designed with adjustable performance of hydrovoltaic devices as a power system for micro‐electronic devices. The flexible hydrovoltaic device structure that only consumes renewable energy is low‐cost, non‐polluting, and highly sustainable, achieving a satisfied output power density exceeding 124.5 µW·cm−2 (2075 µW·cm−3). Both experimental results and theoretical calculations reveal that the working principle of the device depends on the evaporation potential rather than the streaming potential. In addition, the integration of multiple devices makes it easy to drive electronic devices for correct operation and energy storage. For the first time, this integrated hydroelectric photovoltaic device has demonstrated the ability to charge commercial button‐type lithium batteries with great success. The current work combines asymmetric structure and tunable performance, providing an alternative method for high‐efficiency hydrovoltaic devices with high power density.

Elucidating the Iron‐Based Ionic Liquid [C4py][FeCl4]: Structural Insights and Potential for Nonaqueous Redox Flow Batteries

AbstractIn this study, a low‐melting organic‐inorganic crystalline ionic liquid compound, N‐butyl pyridinium tetrachlorido ferrate (III) is described. The material can easily be synthesized using a one‐pot approach in an ionic liquid medium. Single‐crystal X‐ray diffraction confirms that the basic inorganic block is [FeCl4]−, which is counterbalanced by an N‐butyl pyridinium cation. The compound exhibits a melting point of 37.6 °C by differential scanning calorimetry, which is among the lowest values for a pyridinium‐based metal‐containing ionic liquid. The material shows promising electrochemical behavior at room temperature in both aqueous and nonaqueous solvents, and at elevated temperatures in its pure liquid state. Given its appreciable solubility in both water and acetonitrile, the compound can act as a redox‐active species in a supporting electrolyte for redox flow battery applications. These classes of low‐melting ionic solids with long‐range order and interesting electrochemical applications are potential candidates for a range of green energy storage and harvesting systems.