There hasn’t been much progress in batteries the past 200 years, not enough for affordable cars, let alone far more essential freight vehicles.
The very heavy, 4,647 pound Tesla Model S gets most of its mileage from aerodynamics, reduced rolling resistance, light-weight materials, and so on. The Tesla S goes further than other all-electric cars because it has more batteries. Tesla S battery packs weigh 1,323 pounds (plus 350 lbs for the electric motor and inverter) versus 660 lbs for the Nissan Leaf (also pretty heavy at 3,340 lbs).
Batteries are simply not as energy dense as oil. Pound for pound, oil is 500 times more energy dense than a lead-acid battery, and 120 times a lithium-ion battery (roughly, since there are many kinds of li-ion batteries).
So let’s start over and design a high-energy battery from scratch. The first step is to look at the periodic table to choose the best elements.
There are only 118 possible elements to work with, and most of them can be ruled out:
- 39 are radioactive
- 23 are far too scarce or expensive to scale up commercially such as rare earth and platinum group metals
- 6 inert noble gases
- 4+ toxic metals such as cadmium, cobalt,mercury, arsenic
- and others are too heavy, too valuable (gold), hard to recycle, scarce, have too little reduction, oxidation, and other properties essential to making a battery work
Here is Aidan Stranger’s point of view (taken from a comment below): “Alkali metals (and indeed most other metals) have a greater reducing potential the further down the periodic table you go. So if reactivity were the deciding factor, caesium would be the best choice (francium’s not an option because it’s radioactive, extremely rare and very short lived). If cost is the deciding factor, sodium’s a better choice. But lithium is usually preferable for batteries because it’s lightweight; the higher specific energy more than makes up for the lower energy density. But there are more factors to consider. Alkali metals only have one electron each. Something with more outer shell electrons could be more effective. Vanadium (with five) is often used in wet cells. As for fluorine, forget it! Fluorine gas is far too dangerous to have in batteries, and oxygen fluorides are also dangerous and difficult to work with. I’m amazed that anyone’s even contemplated it. Unlike fluorine, cadmium can be contained fairly easily, so has been used for batteries despite its toxicity.”
Another possibility is looking at what elements could produce the highest voltage from the most reducing and most oxidizing elements. The highest potential is nearly 6 volts with a lithium anode (the strongest reducing element) and a fluorine cathode (strongest oxidizing element) of -3.04 & 2.87 respectively). Battery researchers know this and have been trying to develop such a battery since the 1960s. Scrosati et al have an excellent history of Li-F battery research and where we stand on different battery types today if you want to know the technical details.
The material electrons swim through between the anode and cathode matters as well. Cells with aqueous (containing water) electrolytes are limited to less than 2 volts because the oxygen and hydrogen dissociate above this voltage. This is a shame, because water is very inexpensive. Lithium batteries don’t use water but this prevents electrons from flowing as well (high internal impedance) so 2.7 to 3.7 volts are achieved, rather than the maximum 6 volt potential between lithium and fluorine
The laws of physics means that there is no possibility of making a battery that rivals the energy density of oil, ever. So the question is, if a 6 volt lithium-fluorine battery could be built — and it probably can’t — but if it could, would it be energetically cheap and powerful enough to move heavy-duty class 7 & 8 all-electric tractors, harvesters, road construction, and mining trucks?
If so, then is there enough lithium on the planet, including recycling, to make enough batteries for all electric cars, trucks, and utility-scale energy storage and lithium-battery mining trucks to haul ore to refining plants, and so on?
The main elements that lithium are dating are shown below. The rare earth elements aren’t in the battery, but are being used in the electric motor and generator, so even if lithium is recycled, the limits to EV may come from rare earth metals used other components of electric vehicles, which can NOT always be recycled:
by Alice Friedemann, www.energyskeptic.com
Scrosati, B., et al. 2013. Lithium batteries. Advanced technologies and applications. Wiley.
For a more in-depth look at battery chemistry see: Battery and Energy Technologies. Cell Chemistries – How batteries work. Electropaedia. mpoweruk.com