Jiangxi Air power-bank flight policy.

Short answer

Jiangxi Air publishes an official dangerous-goods page with power-bank rules. The page defines power banks as lithium-battery mobile power supplies for external charging of electronic devices, says power banks are strictly prohibited in checked baggage and must be carried on the person or in hand baggage, and says they must not be placed in aircraft baggage racks. Power banks up to 100 Wh do not need airline approval, power banks over 100 Wh through 160 Wh may be carried only with airline approval, each passenger may carry no more than two power banks, and power banks over 160 Wh or with unmarked/unverifiable rated energy are prohibited. China domestic flights also prohibit power banks without 3C marking, unclear 3C marking, or recalled model/batch status.