The lightning rod was added to Minecraft in v1.17. They are used to divert lightning strikes to prevent them from setting structures on fire. They are made from copper ingots.
A lightning rod (via screenshot)
Lightning rods are items that are not naturally generated. They can only be crafted. You can craft lightning rods by placing 3 copper ingots in a 1x3 formation in the crafting grid. You can pick them up by breaking them with a stone pickaxe or better. If any other tool is used, it will drop nothing.
Crafting a lightning rod (via screenshot)
Lightning rods can be oriented in different directions to redirect lightning strikes within a spherical volume having a radius of 128 blocks. During a thunderstorm, the rod will emit particles as an indicator. They will not divert lightning created by tridents. Unlike real-life lightning rods, they don't require a connection to the ground to work.
A lightning rod on top of a house in a thunderstorm (via screenshot)
Lightning rods are very useful items that protect flammable blocks such as wood from lightning strikes. They don't generate naturally but are quite easy to craft.
A. If you have a wooden home, it is highly recommended that you place a lightning rod to avoid your home from burning down.
A. To make a lightning rod, you will need 3 copper ingots.