When this 0.22 Farad, 2.5 Volt super capacitor’s time came, it didn’t go easily. It put up a fight: It let all of its electrolyte out through its bottom and onto the PCB, leaving a hard, crusty layer, and a capacitor that doesn’t work.
It is typically used in place of a standard “battery backup”, and possibly to retain RAM contents between short resets.
Manufacturer: Cooper Bussmann
Type: PowerStor Aerogel Type B, 0.22F 2.5V Capacitor
Digikey Part Number