Why was China paying so much more? Just to ensure they would have enough for their needs?
China procures most of their lithium through trade, so they're tapping the same global markets as everybody else.
For example if there was not enough shipping routes to China from where it's made then that could be an issue. Or if their demand was up, and there wasn't enough unloading capacity for lithium (not sure how this is being shipped over there) then there can be price spikes.
They manufacture basically everything and export a ton
The high lithium prices in China were the Chinese side of the trade restrictions causing economic pain.