Graphene nanosheets (G) and pure, as well as
doped Mg-, Mn-, V-Li4Ti5O12, spinel structure have been
synthesized. As-prepared materials were characterized by Xray powder diffraction (XRD), FT-IR, scanning electron microscopy (SEM), cyclic voltammetry, and constant current
discharge methods. The physical properties, as well as the
possible role of the doped materials in supercapacitors, have
been studied. The hybrid supercapacitor with pure or doped
Li4Ti5O12 (LTO) anode was fabricated afterward to form the
graphene/Li4Ti5O12. The specific energy, specific power, fastcharge capability, lifecycle, and self-discharge of the studied
devices were compared. Metal doping did not change the
phase structure while remarkably improved its capacitance at
high charge/discharge rate. The hybrid supercapacitor utilizing pure or doped Li4Ti5O12 as an anode exhibits high capacitance compared to DLC because of the electrochemical process with intercalation/deintercalation of lithium into the spinel LTO. The capacitance of the hybrid supercapacitor decreases from 207 to 108 Fg−1 when discharged at several
specific current densities ranging from 1 to 10 Ag−1
. In contrast, the capacitance of the DLC is slightly decreased. |
