Rich is absolutely correct.
Dielectric grease is an insulator.
What you want at a battery/ground connection is a rust-proof, highly conductive connection,
What you want to use in these locations is a highly conductive anti-oxidant (anti-corrosion) compound/grease, such as: Kopr-Kote, Kopr-Shield (no longer listed by Eastwood), or NAPA: BK 7652569.
