Synthesis of Nitrogen-Doped Graphene as Highly Effective Cathode Materials for Li-Ion Hybrid Supercapacitors

In this paper, we report the possibility of utilizing nitrogen-doped graphene (N-G) as a novel cathode material for Li-ion hybrid supercapacitors (Li-HSCs) applications. N-G was prepared by a simple one-pot hydrothermal method, followed by freeze-drying in a vacuum treatment. Li-ion hybrid supercapacitors was fabricated using N-G as the cathode along with lithium-ion intercalated compound LiMn2O4 as the anode in an aqueous medium. The energy density of the Li-HSCs can increase up to 22.15Wh kg−1 when the power density reached was 132 W kg−1, and still retained 13 Wh kg−1 at a power density of 2000 W/kg. The LiMn2O4/ N-G Li-HSCs assembly also shows good cyclic performance with about 80% of the initial value retained after 2000 galvanostatic cycles under high rate cyclic conditions. This result clearly indicates that N-G is a promising candidate for future application in a Li-HSCs configuration.