Dielectric grease is suitable for this appliction.
It protects surfaces from corrosion. While
While it is an insulator, when two conductive surfaces are mechanically forced together the grease layer is easily displaced.
In very low contact force situations it may act as an insulator but, even in this application, it is likely to work well.
There are many on web exmples of its use on terminals.
One example only here -
WHAT IS DIELECTRIC GREASE AND WHAT IS IT USED FOR?
" ... dielectric grease is specifically formulated to protect and insulate electric systems. It has many practical uses including automotive tune ups, home electrical work, and recreational vehicle wiring. Because dielectric grease does not dissolve in most liquids, it’s also extremely good for marine and outdoor applications. It can be used to lubricate the rubber parts of electrical connectors, spark plug wires or to protect electrical connections on your boat or recreational vehicle.
Some of the most common uses include Battery terminals. Spark plug boots, Bulb sockets, Trailer connectors, General electrical connections, General plastic or rubber lubrication ... "
Other references:
Difference Between Dielectric Grease and Silicone Grease
- "... Dielectric grease is often used for battery terminals to prevent fusing and corrosion as well as high-energy ignition systems to prevent voltage leakage; however, it can also be used in combination with other various terminals and connectors, such as butt connectors, ring, spade, and heat shrink terminals. ... "
