Capacitate Lightning

Lightning often strikes the Earth's surface. Sometimes it hits a person. Sometimes it causes property damage. The status quo sucks, let's change it.
In the 1700s, Benjamin Franklin did many experiments about the nature of electricity, although the thing with the kite was actually just a thought experiment, and not actually done. In the course of these experiments, he invented the lightning rod. Not only did it protect a house from being struck by lightning, it also harnessed the energy to ring a bell, mostly as proof that it was protecting you. This was later disabled when the repeated bell ringing annoyed his wife and his friends.
Churches at the time often denounced the lightning rod as interfering with the wrath of God. They stopped doing so when churches quickly became the #1 most often struck structure in existence, which made their argument look, at best, patently insane.
Anyway, lightning has considerable energy. Essentially a built up, over sized version of static cling, lightning strikes with around 500 MegaJoules of energy. This is enough energy to run my computer for about 2 months. However, it is all delivered at once, which leads to major grid-problems when the electric grid itself is struck. Equipment literally fries from the sudden burst of energy all at once.
So I propose placing a large metal rod in a lightning-prone area. This rod is connected to a very high capacity diode, then to a very large bank of capacitors. Then another, more conventional, diode, then a bank of batteries. When lightning strikes the rod, the capacitors suck up the energy, then slowly drain it into the batteries. The batteries can slowly power the electrical grid after passing through, yes, another diode. The diodes are to ensure that this setup does not drain backwards, which would uselessly suck energy from the grid. The capacitors store energy, but not very well. Capacitors are mostly useful for their ability to quickly charge and discharge. The batteries should be the deep-cycle kind that can be charged and drain without annoying side effects like battery-memory.
This structure would supplement the energy grid slightly, but not well. Its primary purpose would be to absorb lightning strikes in the area to prevent them from damaging other structures. The added power is just a minor side benefit.