It looks like CATL (Contemporary Amperex Technology Co., Ltd.) has finally cracked the issues with sodium-ion batteries. Sodium is the main element of sodium chloride, which is common salt, and is the most abundant mineral on Earth. It is easy to refine from salt deposits, or even from ocean water, without the by-products of hazardous chemicals that lithium mining has.
Starting in 2023 CATL will begin full production on sodium-ion batteries that surpass the 200 watt/hours per kilogram power storage of lithium-ion batteries. They are cheaper to make, are less harmful to the environment, and use readily available materials. Unlike lithium, sodium is a stable element and is not combustible. Sodium-ion batteries also work without the heat problems of lithium-ion, thus making them safer, and allowing them to be 80% charged in 15 minutes.
These new batteries can be made in the same size and dimensions of lithium-ion batteries meaning they are drop-in replaceable with current devices. Everything from your cell phone to your electric car.
This means less expensive electric cars, with better range and recharge rates.
It also means home power banks become affordable, which is great news for people living off grid. This of course, includes boaters.
Here's great 6 minute video by EyeTech that explains the technology.