Antimatter is a powerful energy source, though somewhat unstable.
Generation One cartoon continuity
Dr. Alcazar created an antimatter formula, which came to the attention of Megatron. Predictably, he wanted it as a source of energy. The doc deleted the formula, but sent it to Chip Chase. Ultimately, Megatron decided that antimatter was simply too unstable to use.
On the other hand, the Ark has an antimatter conversion chamber as part of its power system.