We have come a long way since German inventor, Siegfried Samuel Marcus manufactured the first gasoline powered automobile in 1870. Living in an era where electric cars are set to revolutionize transportation with the promise of a cheaper, environmentally friendly, and smart (AI, self-driving, safe) mode of commute. In-spite of lofty assurances from TESLA and Karma Automotive to century old players like Ford and GM, there are two impediments delaying the transition to natural gas vehicles: cost and driving range.
Gasoline: Not Clean, but Cheap and Convenient
Gasoline is still the preferred choice because of its high specific energy density ~ 12.3 kWh/Kg. The higher the specific energy becomes for a fuel, the longer the driving range extends. The cheapest electric vehicles (EV) in today’s market retail at ~ $ 30,000.00 with a driving range of ~ 100 miles. On the contrary, the most affordable gasoline car costs ~ $12,000.00 and will drive ~ 400 miles with a full tank. A key obstacle to EV adoption lies in the battery pack. Today’s existing automobile batteries are primarily lithium-ion (specific energy~ 0.13 – 0.2 KWh/kg – two orders of magnitude less than gasoline). The cheapest EV, the Leaf by Nissan, charges ~ $270.00 kWh for the price of their EV battery, which is more than twice the estimated $100.00/kWh price point that would popularize battery technology.
Lithium-Air: Front-Runner in EV Battery
Scientists have pushed for decades to search batteries for EVs with comparable specific energy to gasoline. A viable option is lithium-air (Li-air) battery technology. Originally proposed in the 1970s, Li-air garnered significant interest in the 21st century to scientists and EV industrialists. The theoretical specific energy ~ 12.00 kWh/kg of Li-air is comparable to gasoline. The average tank to wheel energy density is 1.7 kWh/kg for a gasoline automotive, which is 5 to 15 times that of which current Li-ion technologies offer. Realizing just 10% of the theoretical specific energy of Li-air when packaged in an automobile can push the EV range to an impressive 1000 miles and beyond.
Achieving the 10% is conceivable with intensive research and long-term technological development. Though, there are challenges to stabilize the highly reactive Lithium in a battery pack and scale it for mass production, several academic and industrial partners have made significant progress to address these obstacles. Incumbent Li-air technology developers and stakeholders range from startups and government labs to leading corporations.
Industry Adoption and Future Prospects
The technology development cycle is nearing its completion for using Li-air in a mass manufactured EV. Volkswagen is (believed to be) working to install the celebrated Golf EV lineup with a Li-air battery pack, tripling the driving range. TESLA recently obtained a patent related to metal air batteries.
TESLA also announced the unveiling of a semi-truck that delivered substantial reduction in cost of cargo transport. This may become the first mass-manufactured Li-air powered automobile.
Smaller sized, potentially cheap batteries like Li-air with high energy density further unravel the potential of electric powered aircrafts for long distance passenger and cargo transport. In the short range, fun to fly ones are already up for grabs.
