Looking for batteries in Nature

Schematic of aqueous organic redox flow battery (ORBAT). Credit: Bo Yang et al./Journal of the Electrochemical Society

Life is all about making order out of chaos and this requires energy, or better the transformation of energy from one form to another. These transformation can only take place when the source is available and the destination is available as well...

Take a leaf: the photosyntheses starts once there is light over a certain thresholds and there are chemicals around to convert light energy into chemical energy.

What if you got a source of energy but you are missing the destination...? Well you need some intermediate way of storing the energy as you get it from the source till the destination becomes available. 

Nature uses "quinones" for that, organic molecules that can store energy.

When we look at our gigantic energy grids the issues are not that much different. We have a number of sources of energy that can be tweaked based on the number of destinations (supply vs demand). However, as in Nature, some of the sources we have learnt to use cannot be tweaked, like wind, and sunshine. You get it when you have it. Similarly demand is difficult to control: if somebody switches on the air conditioning you need to deliver energy to the compressor....

This imbalance between supply and demand nowadays results in an underutilisation of the sources, in particular of the eco-friendly ones since these are not available continuously. What we would need is the capacity to store the energy from these sources as it becomes available and inject it in the grid once there is demand for it.

We need batteries.

Problem is batteries are expensive and pollute, containing metals and dangerous concentration of poisonous materials.  And you need plenty of energy storage if you want to use green energy sources.

Now a team of researchers at the University of South California have invented a battery that mimics Nature in its use of organic molecules to store energy for a while, the quinones. 

The storage is based on water plus these organic molecules. A membrane separates positive and negative charges using the energy provided by the wind turbine and photovoltaic cells. These charges are stored in tanks and the resulting solution can be returned when energy is needed to the membrane for the reverse process. If you need more storage capacity you make bigger tanks. Being the storage solution based on water and organic molecules it is environment friendly and the overall cost is 1/10 of the cost of a lithium battery. And, it can resist to 5,000 recharge cycles (that is 15 years) 5 times more than a lithium battery.

The quinones can be produced out of hydrocarbon, but researchers are looking at the possibility of producing them from carbon dioxide, which would be a further bonus, decreasing the CO2 in the environment.

Author - Roberto Saracco

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