A Sunlight Charging Battery Design

For a couple of years the author of this piece wondered why there where no liquids that could store solar energy into some usefull form. Of course there is water and oil as a heat transfer liquid, but we never read about a liquid that for instance would catch photons and store the energy to release it as heat through the use of a cathalyst. There are chemical reactions you can promote with heat, that are reversible, for instance combining H2 and N2 generates heat, so you can make a closed system where N2 and H2 store the energy and sunlight splits NH3 into these two molecules.

Illustration of lead acid car battery showing lead dioxide plate, lead plate and sulphuric acid

Illustration of lead acid car battery showing lead dioxide plate, lead plate and sulphuric acid

One shape of the question would be an battery in which the electrolyte can be charged with sunlight. This can be so that at one pole the light causes a reaction by which a molecule accepts an electron, and then the molecule needs to go to the other pole to deposit it. Or there is a molecule that is broken into pieces by sunlight but will rejoin if it gets an electron or something. If the above doesn’t make sense its because we really don’t know much about chemistry..


My explanatory drawing

We just can’t believe however that its impossible. To find out more we used fiverr, which is a website where you can find all kinds of experts willing to do work or answer questions. A chemist was not difficult to find. We found Fati, in Multan, Pakistan. With her still limited experience she pointed out that there is a proces called Halothanation, which is replacing a Hydrogen atom by a Cloride atom in molecules under the influence of heat or light. Heat sounds great, if a battery could charge from heat that would be a major thing. Then there is a process called Hetrolytic cleavage. This is when a molecule splits in a way that leaves one or both parts with a charge, positive or negative.


Heterolytic cleavage

There are a number of substances which can be in liquid form that have these two processes, one of them is good old Chloroform. Chloroform is CHCL3, basically a methane molecule with three Hydrogen replaced by Chloride. According to Fati if you expose Chloroform to sunlight is Cl- will go into solution and start traveling around, at least, looking for a positively charged place. The left over Methane will be attracted to electrons. In order to keep the Cl- in solution (it can bind with itself and form Cl2 a toxic gas) we need to add a little bit of NaOh. Worst case salt is fromed which stays in solution.


 The two electrodes need to be of Copper and Zink, now there may be a catch here, because it may be that the battery eats away at the Copper and Zink, or Copper eats away at the Zink, we can’t say for sure. But the interesting property of this battery should be that it gains charge as the sunlight hits it. The sunlight will try to marry Cl2 to the Methane, but also break it apart.


He haven’t constructed the battery yet, and we are very curious what you think about this, or if you know any other molecules or materials that could make up a solar battery. This type of battery could take the form of a solar collector panel, be mounted somewhere and charge itself during the day. No need to have as PV panel and separate batteries! Of course the voltage of such systems is usually low, say 0,5 volt so you would need a number connected in series, as is the case in almost all batteries. The toxicity of chloroform is said to be modest, its a fire hazard as well. Fati tells us it will be ok.

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Solar thermal panels

According to Fati most photosensitive chemicals are pretty toxic, but we just don’t know. Maybe there is an entirely other method that can cause solar energy to be stored in a liquid. Let us know if you have any ideas!