Electric Harvesting Research Articles

Excellent high-temperature piezoelectric energy harvesting properties in flexible polyimide/3D PbTiO3 flower composites

Piezoelectric nanogenerators (PENGs) have been paid great attention in powering electronics via harvesting mechanical energy. Presently, increasing lights are shed onto flexible PENGs capable of working at harsh temperatures. In this research, we report a synthesis of 3D hierarchical PbTiO3 flower-like structure (PTFs) and polyimide (PI)/PTFs composites from which PENGs with excellent high-temperature energy harvesting performances are fabricated. PTFs exhibit a pure phase and a 3D architecture obtained by the hydrothermal method. The PI/PTFs composite PENGs exhibit good electricity-generation performances of Voc ~ 140 V, Isc ~ 103 μA and P ~ 2128 μW. Moreover, high degree of electric power can be continuously generated by the PENG at a wide range of temperature from room-temperature to 300 °C. Excellent durability up to 5000 cycles can be also obtained for the PENG within the temperature range. It has been demonstrated that a PENG in this study lights fifty light-emitting diodes and the resulting electricity is successfully stored in a capacitor. In addition, a real-time high-temperature application is presented where harvesting electricity via the vibration energy of the running automobile engine occurs. The outstanding piezoelectric performance of PENG in this study is attributed to the thermal stability of PI and PT materials, and unique 3D architectures of PTFs in the composites. This work reveals a PI/PTFs composite based PENG exhibiting excellent energy harvesting properties at high-temperatures and the potential applications as microenergy harvesters.

A unique aromatic residue modulates the redox range of a periplasmic multiheme cytochrome from Geobacter metallireducens

Geobacter bacteria are able to transfer electrons to the exterior of the cell and reduce extracellular electron acceptors including toxic/radioactive metals and electrode surfaces, with potential applications in bioremediation or electricity harvesting. The triheme c-type cytochrome PpcA from Geobacter metallireducens plays a crucial role in bridging the electron transfer from the inner to the outer membrane, ensuring an effective extracellular electron transfer. This cytochrome shares 80% identity with PpcA from Geobacter sulfurreducens, but their redox properties are markedly different, thus determining the distinctive working redox potential ranges in the two bacteria. PpcA from G. metallireducens possesses two extra aromatic amino acids (Phe-6 and Trp-45) in its hydrophobic heme core, whereas PpcA from G. sulfurreducens has a leucine and a methionine in the equivalent positions. Given the different nature of these residues in the two cytochromes, we have hypothesized that the extra aromatic amino acids could be partially responsible for the observed functional differences. In this work, we have replaced Phe-6 and Trp-45 residues by their nonaromatic counterparts in PpcA from G. sulfurreducens. Using redox titrations followed by UV–visible and NMR spectroscopy we observed that residue Trp-45 shifted the redox potential range 33% toward that of PpcA from G. sulfurreducens, whereas Phe-6 produced a negligible effect. For the first time, it is shown that the inclusion of an aromatic residue at the heme core can modulate the working redox range in abundant periplasmic proteins, paving the way to engineer bacterial strains for optimal microbial bioelectrochemical applications.

Simultaneous water and electricity harvesting from low-grade heat by coupling a membrane distiller and an electrokinetic power generator

A novel tandem MD-EPG system to harvest low-grade thermal energy is developed for synergetic water purification and electricity generation.

Analyzing the Capabilities of Electric Field Energy Harvesting Using Natural Leaves

Electric field energy harvesters (EFEHs) are reliable and sustainable power sources that may be used to power wireless sensor nodes (WSNs) in urban Internet of Things (IoT) networks, replacing traditional batteries. However, the large-scale deployments begin to pose significant environmental concerns regarding fabrication material degradation and recycling. In this context, this work analyses the performance of the natural green leaves as a replacement for standard electrodes in EFEH developments. To this end, different 10×3 cm2 EFEHs were assembled with raw leaves from the following species Magnolia Obovata, Ravenala Madagascariensis, Acanthus Mollis, and Agapanthus Africanus. Each harvester was evaluated at different drying steps, concluding that natural leaves may collect electrostatic charges related to the urban electric field, which might power ultra-low-energy devices. Experimental results reveal that Agapanthus Africanus electrodes perform best, with an open-circuit voltage (VOC) of 111.88 V and a short-circuit current (ISC) of 229.09 nA. On the other hand, the VOC of Magnolia Obavata leaves achieved 76.76 V, and the ISC was 135.30 nA (the worst case). Although the performance for Ravenala Madagascariensis samples is less than Agapanthus Africanus ones, the size leaf is another critical parameter to design functional devices. Therefore, the experimental section also includes the conceptualization, design, and experimental testing of a functional EFEH prototype called Leaf-EFEH, which is assembled with Ravenala Madagascariensis leaves. Finally, numerous experiments have shown that the proposed Leaf-EFEH can power ultra-low-power devices.

Charge trapping with α-Fe2O3 nanoparticles accompanied by human hair towards an enriched triboelectric series and a sustainable circular bioeconomy.

This work reports a new approach to amending polydimethylsiloxane (PDMS) by supporting α-Fe2O3 nanoparticles (NPs), thereby generating a material suitable for use as a negative triboelectric material. Additionally, human hair exhibits a profound triboelectrification effect and is a natural regenerative substance, and it was processed into a film to be used as a positive triboelectric material. Spatial distribution of α-Fe2O3 NPs, the special surface morphologies of a negative tribological layer containing nano-clefts with controlled sizes and a valley featuring a positive tribolayer based on human hair made it possible to demonstrate facile and scalable fabrication of a triboelectric nanogenerator (TENG) presenting enhanced performance; this nanogenerator produced a mean peak-to-peak voltage of 370.8 V and a mean output power density of 247.2 μW cm-2 in the vertical contact-separation mode. This study elucidates the fundamental charge transfer mechanism governing the triboelectrification efficiency and its use in harvesting electricity for the further development of powerful TENGs suitable for integration into wearable electronics and self-charging power cells, and the work also illustrates a recycling bioeconomy featuring systematic utilization of human hair waste as a regenerative resource for nature and society.

A floating microbial fuel cell: Generating electricity from Japanese rice washing wastewater

Microbial fuel cells (MFCs) are a green technology that can directly convert electrical energy from chemical energy contained in organic wastewater. Rice is the most popularly consumed food in Asia. Rice washing before cooking produces an enormous amount of domestic sewage. Rice washing wastewater (RWW) contains various organic matters, minerals, and vitamins. Therefore, in this study, we utilized RWW as biofuel to operate a floating MFC (FMFC). The FMFC was designed with the air-cathode floating on the biofuel and the anode immersed in the biofuel. This design enables the device to float on wastewater sources and to harvest electricity directly from that source. Baker’s yeast and bacteria existing in a natural pond (natural bacteria) were used as biocatalysts. Experimental results showed that the FMFC could generate electricity from RWW using both the baker’s yeast and natural bacteria. The maximum power density ow the FMFC using the baker’s yeast was 1 mW/m2.

Electricity Generation Using Spring-Powered Floor Pad

Walking is the most common activity in our daily life. When we walk, we lose energy to the floor surface. Vibration is one form of energy that is transferred from our weight on to the floor surface during every step. This energy can be harvested and converted into electrical energy. This research addressed the design and construction of a power generating floor pad which can be used to harvest electricity from human footsteps. The electric generating floor pad features springs mounted on its four corners. When somebody walks though the surface of the floor pad, the springs will be compressed because of the weight of the person causing it to dip down slightly. The shaft of the permanent magnet generator will rotate then rotate, thus voltage is generated. The generator can be connected to a battery so as to store electrical energy. Test performed on the device indicates that it is capable of converting human footsteps to a useful electrical energy to power small electrical devices. The magnitude of the generated voltage can be maximized by applying more force on the floor pad. The discharging time of the battery is longer when there are more footsteps applied to the floor pad. The device can be conveniently installed in the doorways of buildings or other heavy traffic areas. Through this research project, a new option for harnessing green electricity by footsteps is made available focusing on the use of springs and permanent magnet generators.

Electrosprayed Thylakoid-Alginate Film on a Micro-Pillar Electrode for Scalable Photosynthetic Energy Harvesting.

Direct harvesting of electricity from photosynthesis is highly desired as an eco-friendly and sustainable energy harvesting technology. Photosynthetic apparatuses isolated from plants, such as thylakoid membranes (TMs), are deposited on an electrode by which photosynthetic electrons (PEs) are collected from water splitting. To enhance PE collection efficiency, it is critical to increase the electrochemical interfaces between TMs and the electrode. Considering the size of TMs to be around a few hundred nanometer, we hypothesize that an array of micropillar-shaped (MP) electrode can maximize the TM/electrode interface area. Thus, we developed MP electrodes with different heights and investigated the electrospraying of TM-alginate mixtures to fill the gaps between MPs uniformly and conformally. The uniformity of the TM-alginate film and the interaction between the TM and the MP electrode were evaluated to understand how the MP heights and film quality influenced the magnitude of the PE currents. PE currents increased up to 2.4 times for an MP electrode with an A/R of 1.8 compared to a flat electrode, indicating increased direct contact interface between TMs and the electrode. Furthermore, to demonstrate the scalability of this approach, an array of replicated SU-8 MP electrodes was prepared and PE currents of up to 3.2 μA were monitored without a mediator under 68 mW/cm2. Finally, the PE current harvesting was sustained for 14 days without decay, demonstrating the long-term stability of the TM-alginate biophotoanodes.

An experimental exploration of generating electricity from nature-inspired hierarchical evaporator: The role of electrode materials

It is a challenge to harvest both electricity and freshwater from the oceans. This communication demonstrates that the natural-inspired hierarchical evaporator based on multi-walled carbon nanotubes can generate electricity via water evaporation for freshwater production. Furthermore, for the first time, the effect of the nature of exposed electrodes in an electrolyte solution and the distance between two electrodes on the generation of electricity is carefully investigated. We found that the natural-inspired hierarchical evaporator could generate electricity for all time of the day. The proposed natural-inspired hierarchical evaporator is scalable, feasible, and low-cost, providing great potential for direct industrial applications of solar energy on clean water and electricity generations for all time of the day. Moreover, this work also provides additional evidence unravel how electricity is generated by water flow on the surface of carbon materials.

A Magnetohydrodynamic (MHD) Power Generating System: A Technical Review

A magnetohydrodynamic (MHD) power generation technique is a nonconventional electric power harvesting modality in which the electricity is generated from an ionised fluid flow under a magnetic field. The ionized fluid moving under a magnetic field works as a moving electrical conductor and the MHD generator generates electrical energy according to the Faraday’s electromagnetic principle. The concept of MHD based electric power generation was first time introduced by Michael Faraday in 1832, and since then the MHD power generation method has been studied by several groups of researcher. In this paper the MHD technique has been discussed in details followed by a discussion on its components and instrumentation. A technical review on the research works conducted on MHD power generation has been presented and the major developments have been highlighted. The present scenario and the future trends are also discussed along with the challenges of the technology.

Serial Switch Only Rectifier as a Power Conditioning Circuit for Electric Field Energy Harvesting

Because traditional electronics cannot directly use the alternating output voltage and current provided by electric field energy harvesters, harvesting systems require additional regulating and conditioning circuits. In this field, this work presents a conditioning circuit, called serial switch-only rectifier (SSOR) for low-voltage electric field energy harvesting (EFEH) applications. The proposed approach consists of a tubular topology harvester mounted on the outer jacket of a 230 V three-wires electrical cable (neutral, ground, and phase), in which terminals are connected to SSOR. We compare SSOR performance with classic electronic approaches, such as a full-bridge rectifier and voltage doubler. Experimental findings showed that the gathered energy by a 1 m cylindrical harvester increased in approximately 73.3% using the SSOR as a power management circuit. Experimental findings showed that the gathered energy by a 1 m cylindrical harvester increase in approximately 73.3% using the SSOR as a power management circuit. This increase is principally due to the fact that a serial bidirectional switch disconnects the harvester from the rest of the management circuit, enhancing the charge collection process. Although simulated results disclosed that SSOR increased collected energy for smaller-scale harvesters (experimental tests obtained using a 10 cm cylindrical harvester), additional losses in bidirectional switch reduced its performance. In addition, we introduce a comprehensive analysis of EFEH systems based on SSOR according to the mains frequency for future power systems.

Photothermal-structural-fluid behaviors of PV-ETFE cushion roof in summer: Numerical analysis using three-dimensional multiphysics model

PV-ETFE cushion roof combines transparent ETFE films and flexible photovoltaics, making it possible to harvest both electricity and heat from solar energy simultaneously. However, high temperature caused by solar radiation remarkably affects the mechanical behaviors of ETFE foils and converting efficiency of PV due to their thermal sensitivity. To tackle this issue, it is critical to understand the photothermal-structural-fluid performance of PV-ETFE cushion. Due to the difficulty to measure by experiment, this paper presents a three-dimensional mathematical model considering heat-structure-fluid couplings to conduct numerical analysis. Time-dependent analysis and dynamic boundary conditions are applied to study the behaviors which are difficult to observe in experiment. Results explain how photothermal-structural-fluid properties vary in a typical summer day from 9:00 to 17:00. Incident solar radiation and PV modules are two main factors that affect the temperature distribution of the cushion roof and the circulation of internal air. Eight groups of air circulation are found inside cushion chambers during simulating period. Air pressure is mainly determined by average temperature rather than local air flow and uneven heat distribution. It is also found that the worst structural case occurs on the upper layer at noon in terms of structural safety factor. Structural safety of PV-ETFE cushion roof in typical summer days can be guaranteed. These results can be applied further to improve and optimize the design of PV-ETFE cushion roof.

Graphene oxide thin film structural dielectric capacitors for aviation static electricity harvesting and storage

In this paper, we demonstrate the feasibility of using carbon fibre reinforced polymer (CFRP) laminates for the dual functions on aircraft as high load-bearing structural materials as well as for the harvesting and storage of static electricity during flight which can be used to power navigation lights and other electrical systems. CFRP laminate was fabricated into a structural dielectric capacitor (SDC) composite by sandwiching graphene oxide (GO) film between two electrically-conductive carbon fabric layers. To meet the high requirements of aviation applications, the mechanical properties of the GO-based SDC composite were increased using a polymer cross-linking agent in the GO film. This work opens a new concept and possibility of converting the safety threatening static charges into useful electrical energy, which not only reduces the safety hazard, but also improves the energy efficiency of aircraft without compromising the mechanical performance.

Ultralight PEDOT:PSS/graphene oxide composite aerogel sponges for electric power harvesting from thermal fluctuations and moist environment

Abstract Utilizing ubiquitous thermal evaporation for electrical energy harvesting is considered as an effective way to develop future green energy. In this work, we develop a lyophilized-prepared sponge based moist-electric generator with a supramolecular assembly of poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) and graphene oxide (PPGO), which could efficiently harvest electric power from thermal evaporation under extreme thermal fluctuations. More importantly, the open circuit voltage of self-power PPGO generator can reach up to 2.13 V in moist air (RH 73%) under a temperature difference of 110 K without any mechanical energy input, and 0.49 V cm−2 for an apparent area of ~1.25 cm2 under natural evaporation. In addition, the in situ Raman spectra indicate that the spontaneous symmetry breaking induced by assembly of PEDOT:PSS networks is responsible for the enhanced moist-electric power harvesting performance, which provides a convenient paradigm for converting waste heat and humid environmental energy into electricity.

Improved Performance of Microbial Fuel Cell by In Situ Methanogenesis Suppression While Treating Fish Market Wastewater.

The fish market wastewater, which is rich in ammonium concentration, was investigated to explore its ability of in situ suppression of methanogenesis in the anodic chamber of microbial fuel cell (MFC) while treating it and to ensure non-reoccurrence of methanogenic consortia in the anodic chamber during its long-term operations. A lower specific methanogenic activity (0.097g chemical oxygen demand (COD)CH4/g volatile suspended solids (VSS). day) with a higher power density (3.81 ± 0.19W/m3) was exhibited by the MFC operated with raw fish market wastewater as compared to the MFC fed with synthetic wastewater (0.219g CODCH4/g VSS. day and 1.75 ± 0.09W/m3, respectively). The enhanced electrochemical activity of anodic biofilm of MFC fed with raw fish market wastewater than the MFC fed with synthetic wastewater further advocated the enhanced electrogenic activity and suppression of methanogenesis, because of the presence of higher ammonium content in the feed. This, in response, reduced the internal resistance (55Ω), enhanced the coulombic efficiency (21.9 ± 0.3%) and normalized the energy recovery (0.27 kWh/m3) from the MFC fed with fish market wastewater than the MFC fed with synthetic wastewater (92Ω, 15.7 ± 0.3% and 0.13kWh/m3, respectively). Thus, while treating the fish market wastewater in the anodic chamber of MFC, any costly and repetitive treatment procedures for anodic microorganisms are not required for suppression of methanogens to ensure higher activity of electrogenic bacteria for higher electricity harvesting.

A Study of the Movement, Structural Stability, and Electrical Performance for Harvesting Ocean Kinetic Energy Based on IPMC Material

The movement of water in the oceans generates a vast store of kinetic energy, which has led to the development of a wide variety of offshore energy harvesters all over the world. In our energy harvester, we used ionic polymer-metal composites (IPMCs) to convert the ocean energy into electricity. This paper presents a simulated model of an IPMC-based electrochemical kinetic energy harvesting system installed in the ocean and produced using the computational fluid dynamics (CFD) method. The simulation processes focused on the movement and structural stability of the system design in the ocean for the protection of the IPMC module against possible damage, which would directly affect the power output. Furthermore, the experimental tests under real marine conditions were also studied to analyze the electrical harvesting performance of the IPMC system. These results showed that the use of IPMC materials has many advantages as they are soft and durable; as a result, they can respond faster to wave parameters such as frequency, amplitude, and wavelength.

Electrical energy harvesting from ferritin biscrolled carbon nanotube yarn

Various studies about harvesting energy for future energy production have been conducted. In particular, replacing batteries in implantable medical devices with electrical harvesting is a great challenge. Here, we have improved the electrical harvesting performance of twisted carbon nanotube yarn, which was previously reported to be an electrical energy harvester, by biscrolling positively charged ferritin protein in a biofluid environment. The harvester electrodes are made by biscrolling ferritin (40 wt%) in carbon nanotube yarn and twisting it into a coiled structure, which provides stretchability. The coiled ferritin/carbon nanotube yarn generated a 2.8-fold higher peak-to-peak open circuit voltage (OCV) and a 1.5-fold higher peak power than that generated by bare carbon nanotube yarn in phosphate-buffered saline (PBS) buffer. The improved performance is the result of the increased capacitance change and the shifting of the potential of zero charges that are induced by the electrochemically capacitive, positively charged ferritin. As a result, we confirm that the electrical performance of the carbon nanotube harvester can be improved using biomaterials. This carbon nanotube yarn harvester, which contains protein, has the potential to replace batteries in implantable devices.

Design principles for coupled piezoelectric and electromagnetic hybrid energy harvesters for autonomous sensor systems

Abstract Despite the many studies reporting mW-level power output from various hybridized energy harvesters, few succeeded in demonstrating real-life applications such as the commercial Internet of Things (IoT) sensor modules. This owes in large part to the limited time-averaged power output, especially under the requirement for the power-consuming circuitry such as rectifiers and AC to DC converters. At the heart of the limited power lies the lack of detailed analyses and optimization strategies to hybridizing two or more distinct energy harvesters. Here, we first develop design guidelines and optimization strategies based on a parametric model for hybridized energy harvesters coupling two or more distinct mechanisms. The model treats electric current-generating energy harvesters as electric dampers in the spring-mass-damper system and seeks to minimize the total damping consisting of electrical and mechanical damping. We then demonstrate the design guidelines to an oval-shaped hybrid energy harvester consisting of piezoelectric and electromagnetic generators, achieving the time-averaged power output of 25.45 mW at 60 Hz and 0.5 G input vibration. Also, the detailed analyses reveal that the two coupled generators operate in a complementary manner, maintaining a reasonable power output even when one generator suddenly degrades or fails. We finally demonstrate powering a commercial IoT sensor module with the hybrid energy harvester, receiving the sensed information to a smartphone via Bluetooth connectivity.

A State-Of-The-Art Review of Car Suspension-Based Piezoelectric Energy Harvesting Systems

One of the most important techniques for energy harvesting is the clean energy collection from the ambient vibration. Piezoelectric energy harvesting systems became a hot topic in the literature and attracted most researchers. The reason behind this attraction is that piezoelectric materials are a simple structure and provide a higher power density among other mechanisms (electromagnetic and electrostatic). The aim of this manuscript is to succinctly review and present the state of the art of different existing vibrational applications utilizing piezoelectric energy harvesting technique. Meanwhile, the main concentration is harvesting energy from a vehicle suspension system. There is a significant amount of dissipated energy from the suspension dampers that is worthy of being harvested. Different mathematical car models with their experimental setup are presented, discussed, and compared. The piezoelectric material can be mounted in different locations such as suspension springs, dampers, and tires. The technique of implementing the harvester and the amount of power harvested from each location are analyzed. The evaluation of the electrical harvesting circuits and different storage devices for the harvested power are also discussed. The paper will also shed light on the variety of potential applications of the harvested energy.

Electrochemical Strain Evolution in Iron Phosphate Cathodes during Li and Na Intercalation

The ever-growing energy demand associated with the increasing human population, environmental concerns and technological developments puts pressure on society to harvest electricity from renewable sources. Due to their intermittent nature, the adoption of renewable energy depends on further developments in energy storage technology. Although Li-ion batteries dominate the current energy-storage landscape, their application in large-scale energy storage is constrained by continuously growing lithium prices as well as limited Li resources. Sodium-ion batteries have attracted attention in the search for cost-effective batteries with a minimum sacrifice on the performance. Already-existing LIB facilities can be adopted for manufacturing NIBs without requiring expensive upgrades1. Similar to Li-ion batteries, performance of sodium-ion batteries also depends on mechanical integrity of the electrodes and interfacial stability associated with solid-electrolyte interface formation. Physical and chemical properties of Na ions are intrinsically different than Li ions. Lack of insight into the influence of different alkali ions on the interfacial dynamics and mechanical degradations of electrodes limits the design of novel materials. Understanding how electrochemical reactions with different alkali ions affect reaction processes and mechanics of electrodes is required to develop advanced Na-ion batteries. In this work, we investigated in-situ strain generation in iron phosphate cathode during Li and Na intercalation.Digital image correlation technique is used to measure in-situ strain evolution in the composite iron phosphate electrodes2. Iron phosphate (FePO4) was chosen as a model cathode system since both Li and Na can be reversibly intercalated into the FePO4 structure. The composite cathode was prepared by mixing active materials with CMC binder and conductive carbon in 8:1:1 mass ratio, respectively. The electrodes are cycled between 2.6-4.4 V during Li intercalation and 2.0-4.0 V during Na intercalation. Sodium intercalation leads to almost three-times larger strain evolution in the electrode compared to Li intercalation when the electrodes cycled at 50 uV/s. Strain derivative with respect to voltage was calculated using the finite difference method. Local minima in strain derivatives closely matched the current peaks during both Li and Na insertion into the FePO4 structure. Phase transformation in the LFP and NFP, measured by ex-situ XRD corresponds well with the current peaks observed during the cycling3,4. Our results revealed that Na intercalation results in distinct phase transitions and unprecedentedly large electrochemical strains in iron phosphate cathode electrodes compared to Li intercalation .