Subscribe to our free daily newsletters
  Energy News  




Subscribe to our free daily newsletters



ENERGY TECH
Ultrathin device harvests electricity from human motion
by Staff Writers
Nashville TN (SPX) Jul 24, 2017


Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting down. A new, ultrathin energy harvesting system developed at Vanderbilt University's Nanomaterials and Energy Devices Laboratory has the potential to do just that. Credit Michael Todd, Vanderbilt University

Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting.

A new, ultrathin energy harvesting system developed at Vanderbilt University's Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.

"In the future, I expect that we will all become charging depots for our personal devices by pulling energy directly from our motions and the environment," said Assistant Professor of Mechanical Engineering Cary Pint, who directed the research.

The new energy harvesting system is described in a paper titled "Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets" published Jun.21 online by the journal ACS Energy Letters.

"This is timely and exciting research given the growth of wearable devices such as exoskeletons and smart clothing, which could potentially benefit from Dr. Pint's advances in materials and energy harvesting," observed Karl Zelik, assistant professor of mechanical and biomedical engineering at Vanderbilt, an expert on the biomechanics of locomotion who did not participate in the device's development.

Currently, there is a tremendous amount of research aimed at discovering effective ways to tap ambient energy sources. These include mechanical devices designed to extract energy from vibrations and deformations; thermal devices aimed at pulling energy from temperature variations; radiant energy devices that capture energy from light, radio waves and other forms of radiation; and, electrochemical devices that tap biochemical reactions.

"Compared to the other approaches designed to harvest energy from human motion, our method has two fundamental advantages," said Pint. "The materials are atomically thin and small enough to be impregnated into textiles without affecting the fabric's look or feel and it can extract energy from movements that are slower than 10 Hertz - 10 cycles per second - over the whole low-frequency window of movements corresponding to human motion."

Doctoral students Nitin Muralidharan and Mengya Li co-led the effort to make and test the devices. "When you look at Usain Bolt, you see the fastest man on Earth. When I look at him, I see a machine working at 5 Hertz," said Muralidharan.

Extracting usable energy from such low frequency motion has proven to be extremely challenging. For example, a number of research groups are developing energy harvesters based on piezoelectric materials that convert mechanical strain into electricity. However, these materials often work best at frequencies of more than 100 Hertz. This means that they don't work for more than a tiny fraction of any human movement so they achieve limited efficiencies of less than 5-10 percent even under optimal conditions.

"Our harvester is calculated to operate at over 25 percent efficiency in an ideal device configuration, and most importantly harvest energy through the whole duration of even slow human motions, such as sitting or standing," Pint said.

The Vanderbilt lab's ultrathin energy harvester is based on the group's research on advanced battery systems. Over the past 3 years, the team has explored the fundamental response of battery materials to bending and stretching. They were the first to demonstrate experimentally that the operating voltage changes when battery materials are placed under stress. Under tension, the voltage rises and under compression, it drops.

The team collaborated with Greg Walker, associate professor of mechanical engineering, who used computer models to validate these observations for lithium battery materials. Results of the study were published Jun. 27 in the journal ACS Nano in an article titled "The MechanoChemistry of Lithium Battery Electrodes."

These observations led Pint's team to reconstruct the battery with both positive and negative electrodes made from the same material. Although this prevents the device from storing energy, it allows it to fully exploit the voltage changes caused by bending and twisting and so produce significant amounts of electrical current in response to human motions.

The lab's initial studies were published in 2016. They were further inspired by a parallel breakthrough by a group at Massachusetts Institute of Technology who produced a postage-stamp-sized device out of silicon and lithium that harvested energy via the effect Pint and his team were investigating.

In response, the Vanderbilt researchers decided to go as thin as possible by using black phosphorus nanosheets: A material has become the latest darling of the 2D materials research community because of its attractive electrical, optical and electrochemical properties.

Because the basic building blocks of the harvester are about 1/5000th the thickness of a human hair, the engineers can make their devices as thin or as thick as needed for specific applications. They have found that bending their prototype devices produces as much as 40 microwatts per square foot and can sustain current generation over the full duration of movements as slow as 0.01 Hertz, one cycle every 100 seconds.

The researchers acknowledge that one of the challenges they face is the relatively low voltage that their device produces. It's in the millivolt range. However, they are applying their fundamental insights of the process to step up the voltage. They are also exploring the design of electrical components, like LCD displays, that operate at lower than normal voltages.

"One of the peer reviewers for our paper raised the question of safety," Pint said. "That isn't a problem here. Batteries usually catch on fire when the positive and negative electrodes are shorted, which ignites the electrolyte. Because our harvester has two identical electrodes, shorting it will do nothing more than inhibit the device from harvesting energy. It is true that our prototype will catch on fire if you put it under a blowtorch but we can eliminate even this concern by using a solid-state electrolyte."

One of the more futuristic applications of this technology might be electrified clothing. It could power clothes impregnated with liquid crystal displays that allow wearers to change colors and patterns with a swipe on their smartphone.

"We are already measuring performance within the ballpark for the power requirement for a medium-sized low-power LCD display when scaling the performance to thickness and areas of the clothes we wear." Pint said.

Pint also believes there are potential applications for their device beyond power systems. "When incorporated into clothing, our device can translate human motion into an electrical signal with high sensitivity that could provide a historical record of our movements. Or clothes that track our motions in three dimensions could be integrated with virtual reality technology. There are many directions that this could go."

Research paper

ENERGY TECH
Study: Mini cellular antennae helps turn muscle into fat
Washington (UPI) Jul 13, 2017
No matter how much you diet and hit the gym, muscle cells turn to fat as the body ages. Toned bods inevitably become flabby. Blame it on the cilia. New research shows the tiny cellular antennae plays a key role in the muscle-to-fat transformation process. While the realization is unlikely to unlock the fountain of youth, it could help scientists develop new types of regenerative therapi ... read more

Related Links
Vanderbilt University
Powering The World in the 21st Century at Energy-Daily.com


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

ENERGY TECH
Google's 'moonshot' factory spins off geothermal unit

Fighting global warming and climate change requires a broad energy portfolio

Low-carbon trajectory is the only option, European leaders say

Divestment streak continues for British energy company Centrica

ENERGY TECH
Study: Mini cellular antennae helps turn muscle into fat

Optimizing hydrogen-powered passenger ferries focus of Sandia Labs study

Using the stairs just got easier with energy-recycling steps

Giant charge reversal observed for the first time

ENERGY TECH
Unbalanced wind farm planning exacerbates fluctuations

Algeria seen as African leader for renewable energy

Owls' wings could hold the key to beating wind turbine noise

Thrive Renewables delivers mezzanine funded wind farms in Scotland

ENERGY TECH
Non-toxic alternative for next-generation solar cells

More EU praise for progress on renewable energy

Making two out of one

There Will Always be Sun on this Horizon

ENERGY TECH
Laser-Armed Nuclear Icebreakers: What Russia Has in Store for Arctic

Britain must leave EU nuclear body: Verhofstadt

France could close a third of nuclear reactors: minister

Mitsubishi, Assystem take stakes in France's nuclear reactors firm

ENERGY TECH
New biofuel technology significantly cuts production time

Solving a sweet problem for renewable biofuels and chemicals

Cutting the cost of ethanol, other biofuels and gasoline

A whole-genome sequenced rice mutant resource for the study of biofuel feedstocks

ENERGY TECH
Russia boasts of Turkish gas pipeline progress

An IPO in Thailand sparks push for regional energy development

U.N. to help Nigeria look beyond oil for revenue

Brent crude oil passes the $50 threshold in early Thursday trading

ENERGY TECH
ADB warns climate change 'disastrous' for Asia

Scientists upgrade database tracking global temperatures across millennia

Bloomberg outlines plan to quantify US climate efforts

G20: Compromise on climate change, but at what cost?




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement