  In this study, we investigated the graphene-ionic liquid (EMImBF4) interface
to clarify the effects of ambient temperature and potential on the differential
capacitance. We complemented molecular dynamics simulations with density
functional theory calculations to unravel the electrolyte and electrode
contributions to the differential capacitance. As a result, we show: (1) the
relation of characteristic saddle points of the capacitance-potential curve to
the structural changes; (2) the smearing effect of temperature on the local
structure and, consequently, on the capacitance; (3) rationalization of these
observations with the interfacial bilayer model; and, finally, (4) how quantum
capacitance correction dampens the influence of temperature and improves the
agreement with the experimental data. These insights are of fundamental and
practical importance for the application of similar interfaces in
electrochemical energy storage and transformation devices, such as capacitors
and actuators.
