LKE has a lot more shares, its market cap is just half compared...

LKE has a lot more shares, its market cap is just half compared with Vulcan (you might be new to investing if you are comparing share prices like that). But I will list here the main advantages Vulcan has over LKE and other similar projects.

1) "Free electricity" due to the combination with geothermal power. Electricity cost is one of the main worries long terms for high energy processes like DLE, Vulcan solves this problem of the bat. Also in their cost calculations you can see that LKE has almost double costs as compared with Vulcan (due to energy).

2) Green Lithium. LKE says that 1kg of Lithium produced will produce 4-5kg of CO2, that is the same amount as evaporation brine process. While it is true that it will save a lot of water, it cannot really be called green lithium. Vulcan just published a study claiming they can actually capture almost 3kg of CO2 through its process (mainly from producing CO2 neutral electricity). It's Lithium will be sold at a decent premium.

3) European production. The EU wants to boost internal production, so they will certainly help a project like Vulcan.

Obviously LKE is in a much advanced stage (1-2 years) but in the long run Vulcan is a much better company with much better assets.