| Researchers at NSF's Future
Renewable Electric Energy Delivery and Management (FREEDM) Systems Center
have developed a high-performance electrode that allows lithium-ion batteries
to deliver more energy in a smaller space. The Center, headquartered at
North Carolina State University's Centennial Campus, has produced porous
composite nanofiber electrodes made of manganese oxide/carbon (MnOx/C).
The nanofibers were prepared
through a process called electrospinning, which uses an electrical charge
to spin nano-sized particles from a liquid. After additional steps of stabilization
and carbonization, the nanofibers form three-dimensional non-woven membranes
that can be directly used as battery electrodes without the use of any
binding or conductive additive. These nanofibers have been incorporated
into lab-scale coin-type cells and the data from electrochemical testing
is promising. The testing shows that the manganese oxide/carbon nanofiber
electrodes have at least 60 percent higher capacity than state-of-the-art
graphite electrodes.
The Center is also evaluating
the performance of several other types of nanofiber electrodes.
Lithium-ion batteries are
popular in applications including automotive, defense, consumer electronics,
aerospace, and more, because of the batteries' high power density, high
energy-to-weight ratio, and slow rate of discharge when idle. A constant
challenge in improving the performance of these batteries (also known as
Li-ion batteries) has been to increase their power output while reducing
their spatial footprint in the devices they power. Lithium-ion batteries
using the nanofiber electrodes can deliver more energy and power in a smaller
space. In addition, these electrodes have high coulombic efficiency, long
cycling life, and high rate capacities—all characteristics that contribute
to higher performance lithium ion batteries. |
