  In this study, we show that the discharge voltage pattern of a
fractional-order supercapacitor from the same initial steady-state voltage into
a constant resistor is dependent on the past charging voltage profile. The
charging voltage was designed to follow a power-law function, i.e.
$v_c(t)=V_{cc} \left( {t}/{t_{ss}}\right)^p \;(0<t \leqslant t_{ss})$, in which
$t_{ss}$ (charging time duration between zero voltage to the terminal voltage
$V_{cc}$) and $p$ ($0<p<1$) act as two variable parameters. We used this
history-dependence of the dynamic behavior of the device to uniquely retrieve
information pre-coded in the charging waveform pattern. Furthermore, we provide
an analytical model based on fractional calculus that explains
phenomenologically the information storage mechanism. The use of this intrinsic
material memory effect may lead to new types of methods for information storage
and retrieval.
