Metalorganic Quantum Dots and Their Graphene-Like Derivative Porous Graphitic Carbon for Advanced Lithium- Ion Hybrid Supercapacitor

摘要

Lithium-ion hybrid supercapacitors (LICs) are considered as a promising candidate in energy storage systems. Taking the factor of sluggish kinetics behavior, battery-type anode plays a significant role in improving the performance of LICs. Here, onion-shaped graphene-like derivatives are synthesized via carbonization of metalorganic quantum dots (MQDs) accompanied with in situ catalytic graphitization by reduced metal. Notably MQDs, exhibiting water-soluble character and ultrafine particles (2.5-5.5 nm) morphology, are prepared by the amidation reaction. The carbonized sample exhibits highly graphitic tendency with graphitization degree up to 95.6%, and shows graphene-like porous structure, appropriate amorphous carbon decoration characteristic, as well as N-doping and defective nature. When employed as anode material in LICs, it shows high energy density of 83.7 Wh kg(-1) and high power density of 6527 W kg(-1) when the mass ratio of cathode to anode is 1:1 and the operating voltage ranges from 2.0 to 4.0 V. It also possesses the long cyclic stability with the energy density retention maintains at 97.3% after 10 000 cycles at 5.0 A g(-1). In addition, the energy density is further increased by altering cathode/anode mass ratio and extending working voltage. This work provides a novel strategy to develop unique carbon materials for energy storage.