It is destructive to the environment.

The real question is if it is worth the damage to the environment for the lithium? That lithium will make it possible to make more batteries for less money, which then less fossil fuels and more renewables can be used over the entire life of the battery. Further if we start recycling lithium batteries completely, then it is the improvement across the lives of all the batteries made from that lithium minus any damage to the environment caused be recycle each generation of batteries.

For Maine they probably will not see enough of an improvements directly. For the US we might see enough improvements elsewhere to make it worthwhile. For the world we probably would be a net gain of environmental improvement.

The longer the timeframe the lithium can be used to lessen climate change impacts (batteries for cars and renewables) the more likely even Maine would see a net positive versus the damage of mining the lithium to begin with. But that is very hard to quantify and even harder to predict the future (new battery tech might displace current lithium batteries).