AC vs DC charging
AC (alternating) is the slow charge at home, capped by the car's onboard charger; DC (direct) is the fast road charge that goes straight into the battery.
At home you charge on alternating current (AC): the car converts it to direct current with its onboard charger, which sets the speed ceiling (typically a few kW). Ideal for overnight charging.
Roadside fast chargers deliver direct current (DC) straight to the battery, skipping that converter, which is why they're far faster. Using DC now and then is fine; leaning on fast charging, especially in heat, speeds up wear a little.