A few days ago we talked about graphene composites and how they can influence Lithium Ion batteries of the near future. In the ever continuing saga of the search for better batteries, a team from Rice University has turned to Nano-technology.
The American Chemical Society journal Nano Letters reports that the research team has succeeded has packing an entire lithium ion energy storage device into a single nanowire. That’s as microscopic as you can get with a charged device. It portends good things if you are in the business of building nano-machines and nanoelectronics.
In their paper, researchers reported testing two versions of their battery/supercapacitor hybrid. The first is a sandwich with nickel/tin anode, polyethylene oxide (PEO) electrolyte and polyaniline cathode layers. The second compacts the same into a single nanowire. The researchers built centimeter-scale arrays containing thousands of nanowire devices, each about 150 nanometers wide. Remember that a nanometer is a billionth of a meter, thousands of times smaller than a human hair.
Leela Mohana Reddy, a research scientist at Rice and co-author of the paper says, “The idea here is to fabricate nanowire energy storage devices with ultrathin separation between the electrodes. This affects the electrochemical behavior of the device. Our devices could be a very useful tool to probe nanoscale phenomenon.”
The nano-batteries are almost invisible when viewed edge-on. Theoretically, the nanowire energy storage devices can be as long and wide as the applications may require them too. Continuing tests show that the batteries have good charge capacities. The researchers are tweaking the materials to handle repeated charge and discharge cycles, which now drops off after 20 cycles.
Sanketh Gowda, the team’s lead author says, “There’s a lot to be done to optimize the devices in terms of performance. Optimization of the polymer separator and its thickness and an exploration of different electrode systems could lead to improvements.”
Better batteries for nanoelectronics could open up exciting possibilities for both the nano and the macro worlds.
The Hartley Family Foundation, Rice University, National Institutes of Health, Army Research Office and Multidisciplinary University Research Initiative supported the research.
