If they're really arriving this year, I would expect an update that is more recent than Q3 2021.
Lithium-ion batteries have existed for many decades. It's not like nobody ever thought about using sodium, which is the most obvious substitution. The problem is that sodium has a much larger ionic radius, which means that inserting and removing it from the cathode tends to wear that out a lot quicker. As a result, most sodium-ion cathodes are doped manganese oxides, which is basically ignored for lithium batteries since its energy density is low. Even with this, the lifetimes are not ideal.
PNNL announced a breakthrough this July in a nickel-based sodium-ion cathode, but the cycle life (90% at 300, suggesting 80% at ~650) is still significantly shorter than what we expect from lithium (80% at >1000), and any NiO2-based cathode is going to carry an exothermic decomposition risk, electrolyte (Na or Li) notwithstanding. PNNL claims they are competitive with the state of the art in longevity for all Na-ion batteries. Also, the PNNL battery uses 10% cobalt to achieve this.
Lithium-ion batteries have existed for many decades. It's not like nobody ever thought about using sodium, which is the most obvious substitution. The problem is that sodium has a much larger ionic radius, which means that inserting and removing it from the cathode tends to wear that out a lot quicker. As a result, most sodium-ion cathodes are doped manganese oxides, which is basically ignored for lithium batteries since its energy density is low. Even with this, the lifetimes are not ideal.
PNNL announced a breakthrough this July in a nickel-based sodium-ion cathode, but the cycle life (90% at 300, suggesting 80% at ~650) is still significantly shorter than what we expect from lithium (80% at >1000), and any NiO2-based cathode is going to carry an exothermic decomposition risk, electrolyte (Na or Li) notwithstanding. PNNL claims they are competitive with the state of the art in longevity for all Na-ion batteries. Also, the PNNL battery uses 10% cobalt to achieve this.
https://www.pnnl.gov/news-media/longer-lasting-sodium-ion-ba...
I expect CATL to release Na-ion batteries for the very-low-cost vehicle market in China, which is not what Americans have come to expect from cars.