Interesting Lithium Battery on sale

[stevemc181]

Up to 8% better fuel economy. Is this a "Snake Oil" claim, or what? Interesting to see what batteries vehicle manufacturers use, if that is the case.

This from their website:

Being Lithium, the voltage is held higher and longer than a lead acid battery. This means your vehicle will supply a stronger spark to burn fuel more efficiently, giving more power for the same fuel. Increasing fuel efficiency, giving better mileage and savings of up to 8%. Once the fuel is burnt more efficiently the exhaust emissions are decreased and this is better for the environment.

What a load of garbage, this alone would put me off buying anything from these guys!