Police Tech & Gear
with Tim Dees
Time to recharge your shirt
Flexible batteries may be incorporated into clothing
Gadgets get smaller all the time. The first cell phones were the size of large bricks, and were almost as heavy; now they’re smaller than a pack of cards. What hasn’t kept up as well are the batteries that power all of our portable toys. Batteries are heavy, bulky, and rigid. According to research published by the Korea Institute of Science and Technology, it may soon be possible to build batteries into clothing and other flexible housings.
Putting a battery into a flexible package would allow the battery to be spread out over a larger area — distributing weight and reducing bulk. A pliable battery could be built into a load-bearing vest, so that the vest itself would power or recharge the radio, body-worn camera and recorder, flashlight, illumination for working on a roadway, and even a cooler or heater for working in adverse weather conditions.
The problems have been with electrical conductivity and flexibility. There are electrically conductive polymers, but they degrade at low temperatures. The experimental batteries use lithium-coated grapheme as an anode and V2O5 (vanadium pentoxide) grown on graphene paper as the cathode. Graphene is a form of carbon in a lattice of interconnected atoms, one atom thick. Viewed on an atomic scale, it resembles chicken wire. Graphene is the basic structural element of graphite (pencil lead), carbon nanotubes, and fullerenes (carbon spheres).
These latticed carbon structures are currently the hot topic in materials science. Carbon nanotubes form strands that are immensely strong, and are resistant to just about all types of decay or degradation. One of the unresolved problems with the use of carbon nanotubes is what you do with them when you’re done, as they don’t break down for recycling or disposal.
A flexible battery also opens the way for flexible devices. Already available are flexible organic light-emitting diode (OLED) displays that roll up like plastic. You may one day have a smartphone or computer display that you wear on your forearm, and will bend to fit and flex as needed.
Carbon nanotubes may also be the foundation for the next generation of body armor. The high tensile strength of this material makes it far superior to Kevlar or other fibers now used in ballistic vests — it’s the strongest and stiffest material known to man. The so-far-unresolved problems are with manufacturing. It’s still difficult, at best, to produce long strands of carbon nanotubes on an industrial scale. And, as mentioned above, we have to figure out what we’ll do with the material when we’re done with it.
You won’t see batteries woven into your clothing anytime very soon, but they might not be that far off. The consumer electronics industry will power this demand, and public safety may be able to enjoy the benefits.