Supercapacitor(EDLC) has two degradation patterns. One is degradation of the electrochemical system (such as electrode or electrolyte) caused by applying voltage and the other is drying up by the evaporation of electrolyte. In both cases, ESR increases and capacitance decreases.
The final failure is open mode by increasing internal resistance. In order to use supercapacitor reliably over the long term, close attention must be paid to the operating temperature condition.
For details, please see our Technical Note
, "6.Reliability of Murata’s supercapacitors (Failure and degradation)"