Energy storage optimization takes a great deal of wisdom, such as the proper trade-offs between energy density or power density. Batteries, which store energy by separating chemicals and are better for delivering lots of energy, while capacitors, which store energy by separating electrical charges, are better for delivering lots of power (energy per time).
Life would be simpler if both were always available without high cost.
At the AVS 57th International Symposium&Exhibition in Albuquerque, MIT reported on efforts to store energy in thin carbon nanotubes by adding fuel along the length of the tube - chemical energy, which can later be turned into electricity by heating one end of the nanotubes. This thermopower process works as follows: the heat sets up a chain reaction, and a wave of conversion travels down the nanotubes at a speed of about 10 m/s.
A typical lithium ion battery has a power density of 1 kW/kg. Although the MIT researchers have yet to scale up their nanotube materials, they obtain discharge pulses with power densities around 7 kW/kg. They also reported new results on experiments exploiting carbon nanopores of unprecedented size, 1.7 nm in diameter and 500 microns long.
"Carbon nanopores allow us to trap and detect single molecules and count them one by one," said Michael Strano, the first time this has been done, and it was at room temperature.
The single molecules under study can move across the nanotubes one at a time in a process called coherence resonance, which has never been shown before for any inorganic system but underpins the workings of biological ion channels.
