This is exciting news, and I'm glad to see that Nissan didn't just dip its toe in the EV world but is actually putting some serious resources into R&D. Few things can have a bigger impact on the electrification of transportation than fast progress in battery technology.
Nissan is raising capacity by improving the positive electrode, specifically, using nickel and cobalt, not only manganese. The new battery can store about twice as much electricity as batteries with positive electrodes made only from manganese. It is robust enough for practical use, able to withstand 1,000 or so charge cycles.
Nissan estimates that the battery will cost about the same as conventional lithium ion ones to produce, as it contains only a small amount of cobalt, a relatively expensive metal.