In a paper titled ‘Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets’, published on ACS Energy Letters online journal, goes to show how an ultra thin device can harvest electricity from human motion.
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“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 University’s Nanomaterials and Energy Devices Laboratory has built the device using battery technology and layers of black phosphorous which is only a few atoms thick.
The device generates energy whenever external pressure is applied to it. The friction created by the human body while in motion is enough to exert as much pressure on the device to enable it to produce energy.
“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 Nitin Muralidharan, a doctoral student who co-led the research.
The team researched for over three years, exploring the behaviour of battery materials when exposed to external pressure — bending and stretching.
“Compared to the other approaches designed to harvest energy from human motion, our method has two fundamental advantages. 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,” said Pint.
While currently, the device doesn’t produce enough voltage to charge a smartphone effectively, the researchers cite that more research and working on bigger applications will enable them to even power smart clothes in the future.
They’re also exploring the design of electrical devices such as LCD which can run on low voltage.
“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.
Although, currently Pint’s innovation is prone to catching fire under immense pressure situations — per se, ‘putting it under a blow torch’ — but the researchers claim that can be solved too by using solid-state electrolyte on their device.
The device is currently under development, but such innovations are much-needed since maintaining the battery juice in our multiple personal devices can become a hassle at times.