"As an energy storage mechanism, compressed air has certain built-in advantages over lithium ion batteries. An air tank is far cheaper than a battery, quicker to charge, and easy to maintain.
On the flip side, the air-powered car suffers from the same problems that have doomed so many other attempts to move beyond the internal combustion engine: limited range and a lack of refueling infrastructure. Zero Pollution Motors claims to have addressed the range issue with the addition of a small fuel-powered heater, which boosts the efficiency of the air engine. Although the heater gives the lie to the "zero pollution" claim, such a system still represents a considerable efficiency improvement over conventional gasoline-driven cars."