Re-inventing the battery for super fast recharge

Roberto Saracco July 4, 2018 Blog 515 Views

A rendering of the 3D battery architecture (top; not to scale) with interpenetrating anode (grey, with minus sign), separator (green), and cathode (blue, plus sign), each about 20 nanometers in size. Below are their respective molecular structures. Credit: Cornell University

It is almost 220 years since Alessandro Volta invented the “pile” (1799 ad) and although amazing progress has been made the overall architecture of a “battery” has remained pretty similar to that first “pile” (“pila” in Italian, meaning a structure made by many layers, layered one over the other). You have the cathode on one side and the anode on the other (don’t be fooled by some batteries, like the one in the picture where the anode and cathode are placed side by side, inside the case there is a wire connecting the cathode at the bottom of the battery to the top for easy connectivity).

This “pile” architecture is, at least partly, responsible for the long time it takes to recharge a battery. What if one could create a battery with a completely different architecture?

This is what researchers at Cornell have been working on and now they are reporting their result in a paper on Energy and Environmental Science.

Using nano technology they have been able to create a battery that is built bottom up by growing in a 3D space (gyroidal structure) the cathode, the anode and the insulator between them. There is no longer an anode on one side and a cathode on the other, they are completely mingled together (still separated by the required insulator layer).

Left-to-right: The anode is made of self-assembling (automatically grown) thin-film carbon material with thousands of regularly spaced pores (openings), each about 40 nanometers wide. The pores are coated with a 10 nanometer-thick electrolyte* material (the blue layer between the black anode layer, which is electronically insulating but conducts ions . The cathode is made from sulfur. Notice the amazingly convoluted shapes that enormously increasing the surface, thus allowing for greater capacity. Credit: Cornell University

This increases the energy density by orders of magnitude and being the cathode and the anode separated by a few nanometre (rather than cm) the recharge happens in a few seconds. Just imagine: by the time you plug in the battery in the mains it is already charged!

So far it is at the stage of “Proof of concept”. The problem to be solved is the different degrees of expansion of each layer that creates fractures and holes in the structure as the battery charges and discharges. It is at the stage of the Volta ‘pile’. For that one it took around a hundred years before being transformed into something really usable. It shouldn’t take that long for this proof of concept to become a usable technology. The advantages it will bring would be amazing.

Notice, however, that creating very high density storage generates safety issues: think about the cellphones batteries that (very seldom indeed) catch fire and explode. Imagine storing 100 times the energy in those batteries and think what might happen if something goes wrong…