Rice vs. Lawrence Berkeley: Battle of the "Nanobatteries"

Rice University Nanowire Battery
Small batteries constructed of nano-scale components, such as Rice's nanowire battery pictured above, can only supply electricity in the micro-amp range. But that is all the energy you need to power ultra-small sensors and actuators. But for now, it is the marvelous fabrication technology which is noteworthy:

Researchers led by Rice professor Pulickel Ajayan built a hybrid energy storage device, which serves as a battery and a supercapacitor. The first version sandwiched an electrolyte between a nickel/tin anode and a cathode made of a polymer called polyaniline. The cathode also served as a supercapacitor, storing lithium ions in bulk, as this writeup by Rice University explains. The prototype proved that lithium ions would move through the electrolyte and into the cathode.


Then Ajayan and colleagues incorporated this structure into a single nanowire, through a complicated process of etching and chemical washing. The goal is to make nanowires with ultra-thin separation between electrodes, so the device can remain as small as possible.

The completed wire-batteries are about 50 microns tall, which is roughly the diameter of a human hair, according to Rice. _PopSci_via_Physorg

More details at Physorg.

Lawrence Berkeley Labs Graphene Nanobattery_via_NBF
The battery above is meant for bigger things -- to ultimately power an electric vehicle. Although constructed from materials with nanoscale thicknesses, by using thin sheets rather than tiny nanowires, the construction can be scaled up more easily. More from Brian Wang:

Berkeley Lab researchers assembled alternating layers of graphene and tin to create a nanoscale composite. First a thin film of tin is deposited onto graphene. Next, another sheet of graphene is transferred on top of the tin film. This process is repeated and the composite material is then heated to transform a tin film into a series of pillars. The change in height between graphene layers improves the electrode’s performance and allows the battery to be charged quickly and repeatedly without degrading. _NBF

More information from Lawrence Berkeley Labs (link via NBF)

Engineers must design production methods with the use of the final product in mind. That is just as true at the nano level as it is on the macro level. The two "nanobatteries" are not actually comparable, although the Lawrence Berkeley design could be scaled down more easily than the Rice design could be scaled up. But there are doubtless applications for which the Rice nanobattery approach will be used, which would not be suitable for the LBNL's graphene sandwich approach.