Since this is a capacitor they probably actually mean the maximum voltage. Typical commercial supercapacitors have something like a 2.5V maximum voltage. When t

Since this is a capacitor they probably actually mean the maximum voltage. Typical commercial supercapacitors have something like a 2.5V maximum voltage. When told that the capacitor in question had a 1.5V maximum voltage the person writing the article probably tried to make the value relatable. They likely didn't know that the maximum voltage of a capacitor and the nominal output voltage of a battery are fundamentally different sorts of things.