查看更多>>摘要：There is a rapidly growing demand for self-powered technologies in wearable electronic devices that can be integrated with the human body to accomplish various functions. Flexible thermoelectric generators produce electricity from temperature differences and demonstrate huge potential as a power source for these devices. Organic materials have attracted extensive attention in the field of flexible thermoelectric generators due to their unique benefits such as lower prices, small weight, material abundance, convenient solution processability, inherent low thermal conductivity, and intrinsically high flexibility. Although noticeable breakthroughs have been made in obtaining high-performance organic thermoelectric materials, the best ZT achieved from them is still far behind that of inorganic counterparts such as BiTe-based alloys at near room temperatures. In this paper, we overview major advanced research on organic-based flexible thermoelectric generators, starting with the basic principles of thermoelectricity and description of thermal and electrical transport interrelationships. Then, we give a comprehensive appraisal of the state-of-the-art in organic-based thermoelectric materials, their advantages and challenges for thermoelectric applications. It is followed by a critical discussion on several strategies to enhance the thermoelectric properties of these materials. Later, we explain different materials' fabrication methods and compare their technical features. Furthermore, we demonstrate different types of structural designs for flexible organic-based thermoelectric generators, their fabrication methods, and several practical strategies to improve their performance. Finally, we summarize practical solutions to tackle the challenges that organic-based flexible thermoelectric power generation is facing to be established as a key technology to be utilized in next-generation wearable electronic devices.
查看更多>>摘要：With the advanced technologies such as 5 G network and internet of things (IoT), there are incredibly increasing sensors and corresponding applications emerging to benefit our daily lives. However, the power supplies for countless sensors become a serious issue to suppress further expansion of IoT. In this work, a self-powered triboelectric sensor (CN-STS) made of electrospun composite nanofibers is developed towards smart traffic monitoring and management. To meet the requirements of fast-response and high sensitivity for the smart traffic management, transferred charge density is adopted as sensing signals compared to voltage / current outputs for it can perfectly record the subtle differences and suitable for dynamic traffic monitoring. Carbon nanotube is further doped into PVDF nanofibers to improve the electrical output performance and pressure sensitivity. A relatively high sensitivity of 0.0406 mu Cm(-2)kPa(-1) at low pressure range (0-75 kPa) and a sensitivity of 0.0032 mu Cm(-2)kPa(-1) at higher pressure range (75-425 kPa) can be achieved by the CN-STS, indicating that the CN-STS is more sensitive at low pressure range. Moreover, by connecting to cloud IoT services, the functions of traffic flow management, overlapping and speeding vehicle capturing, and plate number recognition are realized by the CN-STS arrays with a compensation circuit. A charge amplifier is utilized in power management to process the charge input signals for better distinguishing the signals from none-vehicles and stabilize the volage output for further reading by the A/D convertor build in Raspberry Pi. The engineered self-powered triboelectric sensors not only open a new potential area for triboelectric nanogenerators but also significantly popularize the IoT industry.
查看更多>>摘要：Cu/Ag foils or conducting pastes were proposed and developed to fabricate the electrodes for triboelectric nanogenerators (TENGs) on support surface. But the technology is limited by the substrate surface morphology, especially complex shape and high roughness substrate. In this study, electroless nickel plating on polyethylene terephthalate surface for TENGs electrode was established, the output performances under different external forces were studied comprehensively to obtain a full understanding of the relationship between the density of electrostatic charge (delta) and strain of polydimethylsiloxane (PDMS) dielectric material. Results showed that PET modified with primer (SiO2 particles-resin mixed liquors) could absorb Pd2+ through coordination effect, which acted as catalyst for the deposition of Ni coating on its surface. The deposition of bead-like structure Ni coating on PET surface with a higher average roughness value (Sr) possessed excellent crystallization and electrical property. The TENGs device with Ni coating electrode was measured and compared. The results showed that the relationship between its output electrical signal and SiO2 content in the primer also presented a similar trend for the Sr. The TENGs device had stable and excellent performances and yielded a maximum open-circuit voltage of 39 V. More importantly, a new calculation method for the PDMS strain of formation delta was proposed by equation of state. It was also revealed that the delta and PDMS strain represented a linear regression relation, and the formation of vertical intercept is due to TENGs device internal resistance. This work proposes a visible solution for the flexible, low-cost and lightweight TENGs, and offer the quantitative information about the influences of dielectric material strain on the output performance which could not be reported so far.
查看更多>>摘要：With the challenges of the energy crisis and related environmental issues, the development and utilization of renewable energy have become a mandatory requirement for the sustainable development of modern society. Recently, triboelectric nanogenerators (TENGs) have been widely utilized in renewable energy sources harvesting, such as solar power, wind power, hydropower and so on. Here, a wheel-disk-shaped TENG based on natural pollution-free cotton is reported for simultaneously harvesting wind and water energy. 8.9 mu A of shortcircuit current and 782 V of open-circuit voltage are obtained by cotton assemble triboelectric nanogenerator (CTENG) under a rotation speed of 210 r/min. The maximum peak power can reach 1.89 mW at a matched load resistance of 330 M omega. Moreover, C-TENG can be used as a self-powered system to power electronic devices and sensing wind speed. This work not only presents a feasible solution for sustainable and clean energy harvesting, but also provides a reliable self-powered sensor for environmental monitoring.
查看更多>>摘要：The practical application of aqueous Zn-ion batteries has been largely plagued by the poor reversibility of Zn anode, mainly associated with the dendritic growth and interfacial parasitic reaction. Hereby, electrochemically stable Zn anode is successfully designed by manipulating nucleation process through the introduction of hydrophilic graphene quantum dots (GQDs). Notably, the enhanced binding effect of GQDs with Zn2+ is aroused from the lower electronegativity of GQDs, which is conducive to accelerating uniform Zn deposition, resulting in the robust Zn anode without dendrites. Concomitantly, interfacial hydrogen bonds are excited by the GQDs with oxygen-containing groups, which is beneficial for mitigating water-induced side reaction and improving Zn ion reaction kinetics. Greatly, polarization voltage of symmetric cells is decreased from 80 to 50 mV at 0.8 mA cm-2, presenting a prolonged lifespan of 2200 h. As a result, the assembled ZIBs with vanadium cathode exhibit superior performance with capacity of 164.3 mAh g-1 after 600 cycles at 1 A g-1. Given this, this elaborate work might inaugurate a potential avenue for rationally tuning the electrode/electrolyte interface evolution towards advanced aqueous batteries.
查看更多>>摘要：High performance moisture-driven power generators were developed by laser induced graphitization (LIG) of sodium chloride-impregnated cellulose nanofiber films (CNFs). CNFs impregnated with different amounts of NaCl were obtained by immersing CNFs in NaCl solutions of various concentrations. A CO2 laser engraver was employed to convert the CNFs to porous graphitic carbon films (GCFs) under ambient conditions. By focusing the laser beam on the top surface of the CNF, the laser intensity was the highest on the top surface and gradually decreased toward the bottom surface. Since the focal temperature of the laser beam was higher than the boiling point of NaCl, the NaCl particles near the top surface evaporated more rapidly, creating a NaCl concentration gradient along the thickness direction. When the GCF was exposed to moisture, the dissociated ions migrated between the top and bottom surfaces, producing an electrical current. The maximum voltage and current outputs were 0.65 V and 550 mu A/cm2, respectively, at 90% relative humidity (RH). Due to abundant dissociated ions, the current output was produced continuously rather than pulsed, and was the highest current reported so far. We demonstrated that six vertically stacked GCFs (each 3 mm x 3 mm x 240 mu m in size) at 75% RH were sufficient to turn on green light emitting diodes (LEDs) operating at an onset potential of 2 V for 48 h without any auxiliary devices, such as rectifier circuits and capacitors.
Choi, JinhyeokWon, SukyoungYoon, Hyeok JunLee, Jong Hyeok...
13页
查看更多>>摘要：Recently, we reported surface fluorination of sulfur-based polymers to introduce a new class of extremely negative triboelectric material. However, the direct surface fluorination requires the use of toxic fluorine gas. In this study, we report the toxic gas-free synthesis of extremely negative triboelectric sulfur-rich polymers via the phase separation of a fluorine-rich polymer, poly(2,3,4,5,6-pentafluorostyrene) (PPFS), from sulfur copolymers. PPFS was physically mixed in situ during the inverse vulcanization of elemental sulfur, a by-product of petroleum refining to prepare the polymer blends. Hot pressing of the blends into films induced the phase separation of the hydrophobic PPFS; subsequently, PPFS migrates to the hydrophobic air interface to minimize the interfacial energy. A triboelectric nanogenerator (TENG) based on the phase separated blend films presented long-term stable voltage and current outputs that are 8-fold and 9-fold higher, respectively, than those of a TENG based on polytetrafluoroethylene (PTFE), a well-known extremely negative triboelectric polymer. We also demonstrate the ability of a TENG based on an 81.1 cm(2)-sized blend film to power 400 series-connected blue LEDs of 3.3 V; a triboelectric open-circuit voltage output of 1362.4 V is obtained under a minimal force of 30 N. The demonstrated phase-separation strategy for fluorine-rich polymers will thus provide insights for achieving low-cost, environment-friendly, and high-performance triboelectric energy harvesting.
查看更多>>摘要：All-solid-state batteries (ASSBs) have gained substantial attention because of their intrinsic safety and potentially high energy density. To enable ASSBs, developing solid-state electrolytes (SSEs) with high electrochemical stability is of foremost significance. Here we report a multi-metal chloride SSEs with an excellent electrochemical stability (up to 4.5 V vs. Li+/Li), which originates from the strong Zr-Cl bonding. In addition, a high room temperature ionic conductivity of 1.58 mS/cm was achieved via increasing the Li vacancies in the structure as well as balancing carrier and vacancy concentration. Coupled with nickel-rich cathodes (LiNi0.83Co0.12Mn0.05O2) and high-voltage LiCoO2 (4.5 V vs. Li+/Li), ASSBs demonstrated superb electrochemical performance. This work provides an in-depth structural understanding of multi-metal chloride SSEs and feasible strategies to realize highenergy-density ASSBs.
查看更多>>摘要：The emergence of triboelectric nanogenerators provides convenience for harvesting mechanical energy from the environment, and the contact-separation mode is one of the most basic operation modes of triboelectric nano -generators. The preparation of the triboelectric nanogenerator of this mode usually requires the addition of third-party spacers or the overall deformation of its own substrate. Here, we propose an engraved patterned spacer triboelectric nanogenerator (EPS-TENG) to get rid of these unfavorable constraints. The spacers used by the EPS-TENG are made by engraving the substrate according to the designed and folded patterns. The engraved pattern spacers can be elastically deformed when subject to mechanical impact, and will automatically recover after the impact force is removed, which is perfectly adapted to external periodic mechanical impacts. The peak power of the device reached 92.34 mu W, and 8.48 mu W of average power could be achieved. The driving demonstration of the timer reveals that the EPS-TENG has great application prospects. The EPS-TENG with such excellent performance can not only contribute to the harvesting of mechanical energy in the environment, but also setting a useful reference for the research of engraved spacer triboelectric nanogenerators.
Park, Sun JaeCho, Yong SooKim, Da BinPark, Kwan Sik...
7页
查看更多>>摘要：Although asymmetric perovskite halides are known to possess viable piezoelectricity, their performance of energy harvesting has been limitedly reported. Herein, we propose the first Pb-free inorganic halide-based thin film harvester having strong capability of power-generation, particularly with additional efforts to enhance the device performance using an unprecedented multilayer structure incorporated with metallic interlayers. Representative high-quality CsSnI3 thin films were prepared by one-step spin coating, and up to four layers were stacked with alternating Cu interlayers. Impressive piezoelectric energy harvesting characteristics of -22.9 V and -1233 nA were attained for the four-layered halide structure after poling, which are highest values recorded thus far for perovskite halide thin films. The origin of the enhanced energy-generation is believed to be directly associated with the increased SnI6-octahedra distortion (with off-centering of Sn atoms) by poling and the extra spacecharge polarization by Cu interlayers.
NSTL
Elsevier