Good vibrations for new energy

Nanowerk  October 20, 2020 Triboelectric nanogenerators (TENGs) can be made at low cost in different configurations, making them suitable for driving small electronics such as mobile phones, biomechanics devices, and sensors. Researchers in Australia provide experimental and theoretical models for augmented rotary TENGs. The power generated by TENGs is found to be a function of the number of segments, rotational speed, and tribo-surface spacing. They applied mathematical modeling combined with artificial intelligence to characterize the TENG output under various kinematics and geometric conditions. Sensitivity analysis reveals that the generated energy and the matched resistance depend highly on segmentation and angular […]

Easy-to-make, ultra-low power electronics could charge out of thin air

Nanowerk  October 14, 2020 An international team of researchers (China, UK, Saudi Arabia) has developed a technology that delivers high-performance electronic circuits based on thin-film transistors which are ‘ambipolar’ in deep subthreshold region. The ‘deep-subthreshold ambipolar’ refers to unprecedented ultra-low operating voltages and power consumption levels. They created printed electronics that meet the power and voltage requirements of real-world applications and opened opportunities for remote sensing and ‘place-and-forget’ devices that can operate without batteries for their entire lifetime. The ultra-low-power printed electronics are simple and cost-effective to manufacture. It can be scaled up to make inexpensive battery-less devices that could […]

This tiny device can scavenge wind energy from the breeze you make when you walk

TechXplore  September 23, 2020 A breeze as gentle as 1.6 m/s (3.6 mph) was enough to power the triboelectric nanogenerator designed by an international team of researchers (China, Singapore). The nanogenerator performs at its best when wind velocity is between 4 to 8 m/s (8.9 to 17.9 mph), a speed that allows the two plastic strips to flutter in sync.[see embedded video]. The device also has a high wind-to-energy conversion efficiency of 3.23%. Currently the device can power up 100 LED lights and temperature sensors. Unlike wind turbines, this device is made of low-cost materials and it can be safely […]

These Underwater Drones Use Water Temperature Differences To Recharge

IEEE Spectrum  September 3, 2020 Many of the robotic gliders and floating sensor stations currently monitoring the world’s oceans are effectively treated as disposable devices. A team of researchers in the US is developing an underwater recharging station for oceangoing drones incorporating self-insulating electrical connector capable of operating while the powered electrical contacts are submerged. They tap phase change caused by the temperature differences between warmer water at the ocean surface and colder water at the ocean depths to generate electricity. By attaching an external energy-harvesting module they have transformed robotic probes into assets that can be recharged and reused […]

Study offers new insights for sun-gathering technologies  August 24, 2020 The direct integration of electrocatalysts with photovoltaic materials provides a strategy to photoelectrochemically power chemical transformations and store intermittent solar energy as fuels. Researchers at the Arizona State University highlight how optical and electrochemical characterization techniques can be coupled with structural information to address to what extent does a selected electrocatalytic coating screen photons from reaching the underlying photovoltaic; coating layers contribute to photocurrent production; and are relatively high or low loadings of catalytic sites advantageous. They used p-type gallium phosphide semiconductor that is interfaced with cobalt porphyrin hydrogen evolution reaction catalysts. Experimental techniques can likely […]

Generator developed for harvesting energy from droplets  July 8, 2020 An international team of researchers (the Netherlands, China) has designed a charge trapping‐based electricity generator (CTEG) for passive energy harvesting from water droplets with high efficiency. The hydrophobic fluoropolymer films utilized in CTEG are pre‐charged by a homogeneous electrowetting‐assisted charge injection method, allowing an ultrahigh negative charge density. By connecting the bottom electrode and top electrode of a Pt wire, instantaneous current is generated from continuously falling water droplets. CTEG devices have shown robustness without appreciable degradation for intermittent testing during 100 days. The approach is applicable for energy harvesting from wave‐like oscillatory fluid motion. it […]

Wide-band-gap semiconductors could harvest sunlight underwater

Physics World  April 17, 2020 Using detailed-balance calculations researchers at the University of New York have shown that underwater solar cells can exhibit efficiencies from ∼55% in shallow waters to more than 65% in deep waters, while maintaining a power density >5 mW cm −2. They showed that the optimum band gap of the solar cell shifts by ∼0.6 eV between shallow and deep waters and plateaus at ∼2.1 eV at intermediate depths, independent of geographical location. This wide range in optimum band-gap energies opens the potential for a library of wide-band-gap semiconductors to be used for high-efficiency underwater solar […]

Drones Use Radio Waves to Recharge Sensors While in Flight

IEEE Spectrum  April 17, 2020 An international team of researchers (Lebanon, Italy) has developed and implemented a RF energy harvesting and wake-up system that scavenges a 2.4 GHz signal from a UAV. It can deliver power wirelessly to remote sensors. The signal transmitted by the UAV is harvested and rectified to DC voltage to power a sensor on the ground. Additionally, the UAV modulates the transmitted signal to encode an address that triggers a particular sensor from sleep mode to active mode. Charging can be initiated from input power levels as low as -18.2~dBm and a sensor can be triggered […]

Penn Engineering’s New Scavenger Technology Allows Robots to ‘Eat’ Metal for Energy

University of Pennsylvania,  April 6, 2020 The metal-air scavenger developed by researchers at the University of Pennsylvania works like a battery by providing power by repeatedly breaking and forming a series of chemical bonds and a harvester as the power is supplied by energy in the chemical bonds in metal and air surrounding the metal-air scavenger. They showed that a range of hydrogel electrolyte compositions can be combined with air cathodes to extract 159, 87, and 179 mAh/cm2 capacities from aluminum, zinc, and steel surfaces at up to 130, 81, and 25 mW/cm2 power densities, which exceed the power density […]

Untwisting plastics for charging internet-of-things devices

Science Daily  April 16, 2020 To use body heat to charge some types of micro-devices and sensors lightweight, non-toxic, wearable, and flexible thermoelectric generators are required. Japan studied the thermoelectric properties of highly conductive thiophene-based polymer, called PBTTT. They doped the polymer with a thin ion electrolyte gel, which is known to improve conductivity that infiltrates the polymer successfully when a specific electric voltage is applied. They found that, without the electrolyte gel, the PBTTT chain is highly twisted. Doping it with a critical amount of electrolyte untwists the chain and creates links between its crystalline parts, improving electron conductivity. […]