A battery, in general, is a composite made up by identical mini batteries that all together provide the full capacity desired. Depending on the way the mini batteries are connected one another you can have different voltage and current (the capacity being the combination of the two).
So saying that a battery is made by batteries is nothing ew, but saying that a battery is made up by billions batteries, well that is new!
And this is what researchers at The University of Maryland have been able to do. First they created a material made of pores consisting of a ceramic sheet with millions and millions of nanopore, so small that even putting all of them together the dimension would be less than a grain of sand.
In this porous material they have embedded the electrolyte that is actually storing the charges. The trick is not that much different from storing charges in a capacitor: you can store charges provided that they are contained between “walls” separating them from the others.
The next step has been to place electrodes on each nanopore, electrodes that are made with a nanotube. The problem of aligning each nanotube to the nano pore has been solved by having each of them self aligning (this follows from the way molecules are binding together).
The single cube containing millions of nanopores can be replicated forming a battery with bigger capacity.
On the one hand the electrolyte provides the high density of charge capacity and on the other hand the nanopores structure provides the battery with capacitor like characteristics. In fact, the battery can be fully recharged in just 12 minutes.
They now have a working prototype available and have got ideas how to further improve the capacity: their target is to increase it 10 times in the commercial product. To make this happen they need to create a manufacturing process to produce the ceramic substrate in large batches.