MoS₂-Graphene Composite Electrode for High Energy Hybrid Li-Ion Capacitors

Abstract

A hybrid Li-ion capacitor represents an emerging class of devices, which results from the coupling of high-energy-density battery-type electrode materials at one side and high-power EDLC electrode at other side. Here, we develop a simple and scalable method including ball-milling, followed by a heating process to synthesize MoS2/graphene composite material. The structural and morphological analyses were carried out by powder X-ray diffraction analysis and scanning electron microscopy. The composite electrode delivers high specific capacity (725 mAh/g at 0.1 A/g and 265 mAh/g at 5 A/g). The hybrid device composed of MoS2/graphene composite electrode as negative electrode and commercial activated carbon as the positive electrode exhibits a high energy density of 117 Wh/kg at 200 W/kg and a maximum power density of 3.9 kW/kg at 79 Wh/kg. The hybrid device showed a long cycle stable Li storage capacity (62% after 5000 cycles at 1 A/g).