Triboelectric nanogenerators are an energy harvesting technology that relies on the coupling effects of contact electrification and electrostatic induction between two solids or a liquid and a solid. ...Here, we present a triboelectric nanogenerator that can work based on the interaction between two pure liquids. A liquid-liquid triboelectric nanogenerator is achieved by passing a liquid droplet through a freely suspended liquid membrane. We investigate two kinds of liquid membranes: a grounded membrane and a pre-charged membrane. The falling of a droplet (about 40 μL) can generate a peak power of 137.4 nW by passing through a pre-charged membrane. Moreover, this membrane electrode can also remove and collect electrostatic charges from solid objects, indicating a permeable sensor or charge filter for electronic applications. The liquid-liquid triboelectric nanogenerator can harvest mechanical energy without changing the object motion and it can work for many targets, including raindrops, irrigation currents, microfluidics, and tiny particles.
As a well‐known phenomenon, contact electrification (CE) has been studied for decades. Although recent studies have proven that CE between two solids is primarily due to electron transfer, the ...mechanism for CE between liquid and solid remains controversial. The CE process between different liquids and polytetrafluoroethylene (PTFE) film is systematically studied to clarify the electrification mechanism of the solid–liquid interface. The CE between deionized water and PTFE can produce a surface charges density in the scale of 1 nC cm−2, which is ten times higher than the calculation based on the pure ion‐transfer model. Hence, electron transfer is likely the dominating effect for this liquid–solid electrification process. Meanwhile, as ion concentration increases, the ion adsorption on the PTFE hinders electron transfer and results in the suppression of the transferred charge amount. Furthermore, there is an obvious charge transfer between oil and PTFE, which further confirms the presence of electron transfer between liquid and solid, simply because there are no ions in oil droplets. It is demonstrated that electron transfer plays the dominant role during CE between liquids and solids, which directly impacts the traditional understanding of the formation of an electric double layer (EDL) at a liquid–solid interface in physical chemistry.
The mechanism behind the contact electrification between liquid and solid remains controversial. According to experimental results and theoretical calculations, the contact electrification of ionic liquids and solids is caused by both electron transfer and ion transfer. Furthermore, the contact electrification between nonionic liquids and solids is mainly due to electron transfer.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Electrowetting technique is an actuation method for manipulating position and velocity of fluids in the microchannels. By combining electrowetting technique and a freestanding mode triboelectric ...nanogenerator (TENG), we have designed a self-powered microfluidic transport system. In this system, a mini vehicle is fabricated by using four droplets to carry a pallet (6 mm × 8 mm), and it can transport some tiny object on the track electrodes under the drive of TENG. The motion of TENG can provide both driving power and control signal for the mini vehicle. The maximum load for this mini vehicle is 500 mg, and its highest controllable velocity can reach 1 m/s. Freestanding TENG has shown excellent capability to manipulate microfluid. Under the drive of TENG, the minimum volume of the droplet can reach 70–80 nL, while the tiny droplet can freely move on both horizontal and vertical planes. Finally, another strategy for delivering nanoparticles to the designated position has also been demonstrated. This proposed self-powered transport technique may have great applications in the field of microsolid/liquid manipulators, drug delivery systems, microrobotics, and human-machine interactions.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Triboelectric nanogenerators (TENGs) have been widely applied for energy harvesting and self-powered sensing, whereas smart deformable materials can be combined with the TENG to acquire a more ...intelligent and self-adaptive system. Here, based on the vapor-driven actuation material of a perfluorosulfonic acid ionomer (PFSA), we propose a type of humidity-responsive TENG. The integrated TENG array can automatically bend to the desired angles in response to different humidity conditions, and thus, it can effectively collect energy from both wind and rain drops, where the power density can reach 1.6 W m–2 at a wind speed of 25 m s–1 and 230 mW m–2 under rainy conditions. Meanwhile, this TENG array can fully lay down in dry weather, using the reflective surface to reflect sunlight and heat radiation. The vapor absorption process of the PSFA film can also result in the charge accumulation process. Accordingly, relying on the strong absorption capability of PFSA, a TENG-based vapor sensor with high sensitivity has been developed for monitoring chemical vapor leakage and humidity change. This work opens up a promising approach for the application of the humidity-responsive materials in the field of energy harvesting and self-powered sensors. It can also promote the development of TENG toward a more intelligent direction.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
In recent years, wearable triboelectric nanogenerators (TENGs) and related on-skin nano-systems are drawing massive attentions due to their potential applications in sensory devices, electronics ...skins and portable energy packages. However, most of these TENG devices still employ adhesive tape to attach on human skin, which may cause many side effects, such as inflammation, allergy and discomfort symptoms in the long term. Therefore, it is quite necessary to find a simple and skin-friendly bonding method to directly stick TENG to human skin. Here, we fabricated a blended nanofiber membranes (NM) which is obtained by the mixed electro-spinning technique using polyvinyl alcohol and polyvinylidene fluoride nanofibers. This blended NM can directly attach on skin with the help of a tiny amount of water and no uncomfortable symptoms or allergy can be found during a long period of operation. The TENG device based on this NM can not only achieve good output performance, but also realize a wearable energy generator with inflammation-free and highly gas-permeable characteristics. The blended NM have excellent air permeability (Gurley value = 1.4 s/300 ml-3.3 s /300 ml). The demonstrated concept of this skin-friendly bonding method and NM-based TENG have promising applications in the field of wearable/potable sensory devices, electronics skins, artificial muscles, flexible robots and so on.
In this paper, we designed and fabricated one kind of blended nanofiber membrane using mixed electrospinning technique with different mixing ratios in soluble PVA nanofibers and insoluble PVDF nanofibers. This blended nanofiber membrane is applied to the NM-based TENG device, which has many excellent characteristics, such as inflammation-free, gas-permeable and allergy-free. The NM-based TENG device has rich promising applications in the field of flexible/wearable electronic devices, such as flexible robots, electronic/smart skin, wearable electronic devices. Display omitted
•We designed and fabricated a blended NM using mixed electrospinning technique, which are inflammation-free and gas-permeable.•The adhesive force on skin with our fabricated NM can tolerate 15.6 N, approaching the value of 17.5 N with kapton tape.•When humidity is less than 55 %, the NM can suppress charge leakage, and improve the output performance of TENG device.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The widespread vibration is one of the most promising energy sources for IoT and small sensors, and broad-frequency vibration energy harvesting is important. Triboelectric nanogenerators (TENGs) can ...convert vibration energy into electrical energy through triboelectricity and electrostatic induction, providing an effective solution to the collection of broad-frequency vibration energy. Also, the power supply in constrained and compact spaces has been a long-standing challenge. Here, a miniaturized power supply (MPS) based on a broad-frequency vibration-driven triboelectric nanogenerator (TENG) is developed. The size of the MPS is 38 mm × 26 mm × 20 mm, which can adapt to most space-limited environments. The TENG device is optimized through theoretical mechanical modeling for the external stimuli, it can efficiently harvest vibrational energy in the frequency range of 1-100 Hz and has a high output power density of 134.11 W/cm
. The developed device demonstrates its practical application potential in powering small electronics like LEDs, watches, and timers.
Although graphitic carbon nitride nanosheets (CNs) with atomic thickness are considered as promising materials for hydrogen production, the wide band gap (3.06 eV) and rapid recombination of the ...photogenerated electron–hole pairs impede their applications. To address the above challenges, we synergized atomically thin CNs and graphene quantum dots (GQDs), which were fabricated as 2D/0D Van der Waals heterojunctions, for H2 generation in this study. The experimental characterizations indicated that the addition of GQDs to the π-conjugated system of CNs can expand the visible light absorption band. Additionally, the surface photovoltage spectroscopy (SPV) confirmed that introducing GQDs into CNs can facilitate the transport of photoinduced carriers in the melon chain, thus suppressing the recombination of charge carriers in body. As a result, the H2 production activity of the Van der Waals heterojunctions was 9.62 times higher than CNs. This study provides an effective strategy for designing metal-free Van der Waals hetero-structured photocatalysts with high photocatalytic activity.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Wind energy has played a reasonable proportion in the current energy structure, extracting energy from wind sources attracts extensive attention in the era of global carbon neutrality. However, ...traditional wind turbine based on electromagnetic generator are not economic in some cases, the new technology demand for complementing conventional approaches is proposed. Recently, the emerging triboelectric nanogenerator (TENG) technology based on the coupling of contact electrification and electrostatic induction have been widely researched and utilized to scavenge wind energy, with the advantages of high efficiency, low cost and portability. Here, the recent advances of wind harvesters based on TENG are reviewed, where the material, structure design, power management and the developed strategies to optimize the performance of TENG-based wind harvesting system are summarized. Meanwhile, the hybridization of TENG with other types of energy harvesting techniques is discussed. Finally, the application, outlook and challenge in the growth of TENG-based wind harvester are outlined.
Here, the recent advances of wind harvesters based on triboelectric nanogenerators (TENG) are reviewed. The Strategies to improve the performance of wind driven TENG (WD-TENG) from the perspectives of material, structure optimization and power management are demonstrated. Meanwhile, the applications and development trend of WD-TENG are proposed. Display omitted
•Strategies to improve performance of WD-TENG from aspects of material, structure and power management are demonstrated.•The hybridization between TENG and other technologies for developing compound wind energy harvesters are demonstrated.•The applications of WD-TENG are discussed, including powering portable electric devices, sensing system, etc.•The existing challenges and trend of development of WD-TENG in the future are proposed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Deep learning methodologies have revolutionized prediction in many fields and is potential to do the same in the petroleum industry because of the complex oil-gas reservoir. A limitation remains for ...dense shale exploration in that the shales with invisible bedding are difficult to characterize measurably because of the considerable complexity of the geological structures. The oblique-incidence reflectivity difference method (OIRD) is sensitive to the surface features and was used to obtain a layered distribution of dielectric properties in shales. In this paper, we report a combination of OIRD and deep learning method to identify the dielectric anisotropy of an invisible-bedding shale. The model performs well and clearly identifies the bedding of the shale based on the output values associated with the probability. Only a single direction was determined to have laminations with widths of 20-. The anisotropy features detected by OIRD also existed in the invisible-bedding shale and were caused by the smaller cracks and denser particles' orientation relative to general shales. As current dense reservoirs include rich invisible-bedding shales, we believe that the OIRD method combined with deep learning method can help improve the exploration efficiency of shale reservoirs.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A tactile sensor should be able to detect both normal and tangential forces, which is mandatory for simulating human hands, but this fundamental function has been overlooked by most of the previous ...studies. Here, based on a triboelectric nanogenerator (TENG) with single‐electrode mode, the fully elastic and metal‐free tactile sensor that can detect both normal and tangential forces is proposed. With tiny burr arrays on the contact interface to facilitate the elastic deformation, the detected normal pressure by the device can reach to 1.5 MPa with a sensitivity of about 51.43 kPa V−1, and a large range of tangential forces can be detected ranging from 0.5 to 40 N with rough sensitivity of 0.83 N V−1 (0.5–3 N) and 2.50 N V−1 (3–40 N). Meanwhile, the applied tangential forces from different directions can also be clearly distinguished by the four‐partitioned electrode structure. Moreover, a shield film is coated on the top surface of the device, which can screen the electrostatic interference and enhance the repeatability of the device. The demonstrated concept of this self‐powered tactile sensor has excellent applicability for industrial robotics, human–machine interactions, artificial intelligence, etc.
A fully elastic, tactile sensor that can detect both normal and tangential forces is proposed. The device detects normal pressure up to 1.5 MPa and a large range of tangential forces can be detected, ranging from 0.5 N to 40 N. The applied tangential forces from different directions can all be clearly distinguished.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
