Americium-243 – $180 Million/ Kg

Americium is a scarce element that comes about after nuclear reactions of heavy elements. Yes, you guessed it, this element is highly radioactive and can cause severe issues if mishandled or misplaced.

Due to its radioactive nature, the element hasn’t gotten many uses, but its counterpart, Americium-241, is used in smoke detectors. Lately, scientists have experimented with the insanely expensive element to be used in batteries. Not household batteries but for objects in space due to their high half-life. As for its value, Americium-243 is going for a wild 180 million dollars per kg.