Is it okay to leave a lithium-ion battery on the charger overnight?

It’s generally safe for modern devices due to built-in circuitry, but it’s best to avoid it for long periods as it can stress the battery, slightly shorten its lifespan, and poses a small fire risk with faulty equipment or chargers, so use the manufacturer’s charger and unplug when fully charged if possible to optimize battery health and safety. 

HFH 3.7V 15ah 20ah 35C 70C high discharge rate Li Ion Nmc Prismatic Lithium Ion Battery

hfh-tech Prismatic aluminum Shell NMC battery cell is widely used in Electric vehicles, electric bicycles, tricycles, scooters, golf carts