electrostatics - What defines the maximum charge a capacitor can store?

The formula for a capacitor discharging is $Q=Q_0e^{-\frac{t}{RC}}$ Where $Q_0$ is the maximum charge. But what property defines the maximum charge a capacitor can store?

If it depends on capacitance then that means it depends on the voltage you put across the capacitor, but how can any capacitor "cope" with any voltage?