This article is pretty low quality. The claim that the new million mile battery technology is coming to the China Model 3 first is not supported by a source and contrary to what people who follow this stuff closely have been saying.
The partnership with CATL is rumored to be for providing Lithium Iron Phosphate (LFP) cells for made in china Model 3 & Y. The million mile battery technology is rumored to be a combination of technologies that Tesla will use to manufacture batteries themselves w/o a partner. The million mile battery will probably be reserved for their higher end models in the near term while they continue to use Panasonic and CATL for some time while they ramp up production of their own cells.
The best source for info on all this that I've found is YouTube channels like Hyperchange