Graphene decorated with molybdenum dioxide nanoparticles for use in high energy lithium ion capacitors with an organic electrolyte

An electrode material consisting of graphene decorated with molybdenum dioxide nanoparticles (G–MoO2) is developed. The material exhibits not only a high specific capacitance but also an excellent cycling performance as well as good rate capability in lithium ion capacitors (LICs). The specific capacitance of the G–MoO2 containing 10 wt% G reaches 624.0 F g−1 at a current density of 50 mA g−1, much higher than 269.2 F g−1 for the MoO2 particles alone. Even at a current density of 1000 mA g−1, a high specific capacitance of 173.2 F g−1 is obtained. The capacitance retention remains 91.2% after 500 cycles. Moreover, G–MoO2 provides a high specific energy density of 33.2 W h kg−1 at a power density of 3000 W kg−1. The influences of the synergistic effect of nanostructured MoO2 and conducting G on the electrochemical performance of the LICs are discussed.