Lithium powered mild hybrids - Are they worthy?

Lithium powered full hybrid concept, Toyota's FT-HS

Everyone knows the future of hybrid cars and electric cars seems absolutely dependent upon cost-effective, reliable and safe lithium-ion batteries. Without such batteries, forget the Chevy Volt, forget a 100 mpg Prius, forget plug-in hybrid vehicles.

Obviously, however, if li-on batteries are successful, the entire automotive world will be turned upside down and change forever.

Nonetheless, even if lithium achieves reliability and safety, it might take a bit longer to achieve cost-effectiveness. Yet, small lithium-ion batteries are cost-effectively successful in power tools, phones and, usually, notebook computers.

Thus, might not small lithium battery packs be the next best step for hybrid vehicles? For example, might - dare I say it - lithium be perfect for mild hybrid vehicles? Additionally, small battery packs for mild hybrids might, initially, be safer and more reliable because mild hybrids aren't as battery-dependant as full hybrids.

Consequently, couldn't such mild hybrids significantly help increase the mass production of lithium batteries enough to help scale down the cost of such batteries for all hybrid and electric vehicles?