In pure lubricants, current is not being conducted. What impurity should be added to the pure lubriant to make it conduct current and what amount of that impurity should be added to what amount of lubricant?

The amount of information you gave isn't enough to tell. Graphite is a lubricant and is conductive, but if you only added a small amount to some non-conductive lubricant, it wouldn't make it conduct current. I think you need more information.