Much like the plates inside of your car’s battery, its terminals are made of lead. Lead is resistant to corrosion, and the terminals are quite simple to clean using baking soda and water.
A severely corroded or damaged terminal that does not make good electrical contact may cause a total loss of power. … While they are a very simple and inexpensive component, battery terminals do play a very important role in the overall functionality of the vehicle’s electrical system.
The connecting cables are almost always terminated in brass clamps. As stated, older ones were lead.
The difference between battery terminals is this:

And cabled clamps to go onto the battery terminals is this:

Battery terminals, are sometimes called “posts”. Which is not a common name. now very popular are lead and brass.
Although lead terminals are cheaper than brass ones, they are not as efficient at holding on or resisting repeated clamping and unclamping. The brass does not degenerate as fast as lead either, it is more resistant to scrape cleaning and wire brushing.
You can also tighten the brass connectors to the battery terminals, or posts, much harder than the older lead counterparts.