Preventing 'black wire syndrome' with sacrificial anodes

I have an application where a Ni-Cd battery is causing corrosion along the battery lead back to a circuit breaker. This is a negative polarity system meaning the positive post of the battery is common with earth ground (telecom system). The wiring is copper. The guts of the breaker contain stainless steel springs and 'plated parts'. I have not taken one apart to identify the plated parts.

I've researched and found some possible instigators of what is described as 'black wire syndrome' including moisture, PVC (chlorine) insulation on wires, etc. My question is this. Would it be possible to hang a sacrificial material off the negative lead that would be the primary target for the corrosion, thus extending the life of the circuit breaker? If so, what would this material be?