That's assuming they will only be charged from power sourced from coal plants.
Each year and even month that passes focus on climate change worldwide is prompting many governments and countries to move more and more into solar. As solar technology becomes cheaper and so do lithium batteries more and more electricity will move to cleaner sources of generation. Only a bit of googling will prove this.
As more and more renewable sources come online, the need for storage will also be required. This means more Lithium. Also don't forget this is only the EV industry. Use of lithium in storage batteries is also steadily increasing.
For the US there most definitely is reason for them to catch on. Additionally if there wasn't many, other large car manufacturers probably wouldn't rush in either..
Another example (non-US related) India declared it wants to become 100% EV country by 2030, I wonder what kind of demand that implies???
http://economictimes.indiatimes.com...by-2030-piyush-goyal/articleshow/51551706.cms
US Trends: http://www.seia.org/research-resources/solar-industry-data
The U.S. solar industry continued on its
record-breaking trajectory in Q2 2015 with 1,393 megawatts (MW) of installed solar capacity, making this the largest Q2 in history. As has been the case over the last 18 months, the residential and utility-scale markets led the way, installed 463 and 729 MW, respectively.
"Through the first half of the year, the solar industry has supplied 40% of all new 2015 elecric generating capacity - more than any other energy technology. With more than 5,000 MW of installed solar capacity projected over the second half of 2015, the U.S. solar industry is expected to reach nearly 8,000 MW for the year, and 28,000 MW in total.
Other key takeaways:
- There are now over 22,700 MW of cumulative solar electric capacity operating in the U.S., enough to power more than 4.6 million average American homes.
- With over 135,000 installations in the first half of 2015, nearly 784,000 U.S. homes and businesses have now gone solar and a new solar project was installed every 2 minutes.
- Growth in Q2 was led by the utility-scale sector, which posted its largest quarter of the year at 729 MW, and the residential sector, which grew 70% over last year to install 473 MW and will likely surpass its 2014 total in Q3.
- Since the implementation of the ITC in 2006, the cost to install solar has dropped by more than 73%.
- While residential costs have dropped by 45% since 2010, utility-scale costs have dropped more significantly, with recent contracts at prices below $0.05/kWh. "
Taken from article linked above. 
