Body Fluid Powered Bio-Batteries

RPI’s super-thin bio-battery!

(By, Kevin Le)

Batteries are essential to almost every single electronic device under the sun.  Yet for something so practical, the standard AA or lithium-ion battery have a whole list of problems associated with them.  Over time they can have trouble maintaining power, and lose power all together.  Other batteries leak deadly chemicals and even explode.  A group of scientists at Rensselear Polytechnic Institute (RPI) hope to change that.  They have developed a super-thin “bio-battery” which runs on electrolytes – including the electrolytes found in natural body fluids, such as sweat, tears, blood, and even urine.  Although these bio-batteries seem to be mere novelties in electronics, the implementations of such a miniscule battery have the ability to change the way energy is used in electronics in ways never imagined before.

One of the greatest, if not the greatest, attribute of RPI’s bio-battery is the size of the battery.  Not only is the battery small, but the bio-battery is also as thin as paper – literally.  In fact, at least 90% of the battery is made up of cellulose, the same material used in paper.  The other 10% consists of aligned black carbon nanotubes which make the “paper” black and give the cellulose conductive abilities.  These nanotubes are not layered on top of the cellulose – they are actually embedded into the very fabric of the paper, creating a nanotechnology/paper hybrid known as nanocomposite paper.  Since the battery runs on naturally produced electrolytes, the battery, if inside a body, will stay charged as long as the user is simply alive.  Due to the battery’s small size and paper-thin flexibility, combined with the replenishing power of electrolytes, bio-batteries are ideal for medical purposes.  The thinness of the bio-batteries allow the batteries to be implanted into humans easily, and their flexibility allows the bio-batteries to be “printed out” in massive sheets of electrolyte-powered nanotechnology.  These sheets can be cut out to serve different functions, and can even be clumped together to power medical implants, such as pacemakers, artificial hearts, and advanced prosthetics.

Using the electrolyte properties of RPI’s bio-batteries, doctors can also store these batteries without the need of body fluids. The bio-batteries can be powered from electrolytes from any source, even Gatorade, although scientists typically soak them in in an ionic fluid (salt in liquid form), which contains a plethora of electrolytes, to keep the batteries charged.  Because ionic fluids do not freeze or vaporize at the same temperatures as water, the batteries can withstand a whole scale of temperatures ranging from -100 degrees Fahrenheit (-73.3 degrees Celsius) to a scorching 300 degrees Fahrenheit (148.9 degrees Celsius).  As a result, bio-batteries can be used outside of medical purposes in vehicles such as airplanes or automobiles, which both require light, durable, and energy-sustainable materials.  The researchers at RPI claim that their bio-battery separates itself from most other batteries because of their battery’s ability to act as both a high-energy battery and a high-powered super-capacitor, which allows for large and quick bursts of energy.  Thus, RPI’s bio-battery might have an even wider repertoire of uses than it already has.

Not only are bio-batteries capable of a plethora of implementations, but they are also environmentally friendly, as the battery can be powered by just about anything with electrolytes.  However, RPI’s bio-battery is still years away from being streamlined as large sheets, and the people of RPI are working on making the battery even more efficient than it already is.  For now at least, electronics will have to wait.