Thunder

What would happen if a lightning rod were attached to a Vanadium Redox Battery?

First of all, if you find yourself contemplating such questions, then you are likely as insane as I, and I would suggest you seek professional help immediately.

Moreover, trying to find the answers to such questions is in all likelihood going to be an extremely dangerous endeavor, and you should know what you are doing beforehand.

That out of the way though, can the electricity from a storm be used to charge a Redox Battery? I see no reason why the answer would be a negative. Vanadium Redox Batteries are used to convert electrical charge into chemical potential, and then convert that chemical potential back into electrical charge when needed. They do so by making use of what are known as "oxidation" and "reduction" chemical equations, which take place at the anode and cathode respectively. And there are no barriers to which electron sources can be used to charge them.

Of course, supposing the answer is "yes," the next question is naturally "can they be commercialized?" To which I would point out a couple barriers: both the complexity of the battery, which adds to its cost, and the violence that often accompanies atmospheric electrical discharge, which will impact the lifespan of the entire contraption.

Still though, profit alone is not what drives scientific discovery, and it would be a interesting experiment to say the least.