February 10, 2009
Nested nanotubes promise better
carbon nanotubes inside manganese dioxide nanotubes and you've got
high-capacity, potentially inexpensive electrodes for lithium-ion
The electrodes are made by forming manganese dioxide nanotubes
in a template, then growing carbon nanotubes inside the manganese
dioxide nanotubes. Manganese dioxide is an abundant material, but
researchers have had difficulty making efficient electrodes from it.
The carbon nanotubes help the manganese dioxide withstand repeated
charging and discharging, and they increase the electrical conductivity
of the electrodes.
The nanotubes have a relatively high capacity because both
the manganese dioxide and carbon nanotubes hold lithium ions. The
coaxial nanotube electrodes hold about 500 milliamp hours per gram.
The graphite electrodes used in today's lithium-ion batteries hold
less than 400 milliamp hours per gram.
The coaxial nanotubes could be used in high-capacity lithium-ion
batteries that power vehicles and store electricity generated by renewable
MnO2/Carbon Nanotube Array Electrodes for High-Performance Lithium
Nano Letters, published online February 2, 2009
Related stories and briefs:
nanowires boost batteries -- related research
tin electrodes beat graphite -- related research
Back to ERN home
Energy-related books and products