Chase it down? It says 720 Wh/kg in the thumbnail image.

If that's true, 1300 mile range isn't the big deal. Going much over 400mi is pointless if we build proper charging infrastructure. Use wh/kg advancements to reduce weight, nor increase range.

The big thing is that we can build fully electric airplanes with that kind of wh/kg.

Big if, though. Batteries have been improving by 5-8% per year, and while we're not close to theoretical limits yet, this would represent an unprecedented leap all at once. That claim needs more to back it up than a press release.

Battery density has been improving steadily for the last three decades.

Battery costs keep falling while quality rises. As volumes increased, battery costs plummeted and energy density — a key metric of a battery's quality — rose steadily. Over the past 30 years, battery costs have fallen by a dramatic 99 percent; meanwhile, the density of top-tier cells has risen fivefold

...

With regards to anodes, a number of chemistry changes have the potential to improve energy density (watt-hour per kilogram, or Wh/kg). For example, silicon can be used to replace all or some of the graphite in the anode in order to make it lighter and thus increase the energy density. Silicon-doped graphite already entered the market a few years ago, and now around 30% of anodes contain silicon. Another option is innovative lithium metal anodes, which could yield even greater energy density when they become commercially available.

What's more, the Chinese market is both the leading producer and consumer of battery technology. So its weird to reflexively doubt that a Chinese firm would release a new higher-efficiency battery design.

Given that this is a prototype, its entirely unclear if the model is cost-efficient to mass manufacture or efficiently scalable based on available resources. But I'm hard pressed to discount the claim on its face simply because its got "China" in the headline.