GRAPHENE/ELECTROLYTE INTERFACE IN ELECTROCHEMICAL ENERGY STORAGE: FROM SUPERCAPACITORS TO LI-ION BATTERIES

摘要

Electrical energy storage is key to broader adoption of renewable energy sources and limiting the use of fossil fuels and its environmental impact. Two complementary technologies in electrical energy storage are supercapacitors (also known as ultracapacitors or electrical double layer capacitors) and lithium-ion batteries. Supercapacitors store energy by forming electrical double layers inside the pores of two symmetric electrodes of high-surface-area porous graphitic carbons which could be activated carbons, carbide-derived carbons, or assembled graphene sheets. Lithium-ion batteries store and deliver electrical energy by shuttling ions back and forth between the cathode and the anode through a non-aqueous liquid electrolyte. This paper explores some fundamental issues in these two ways of electrical energy storage: For the supercapacitors, we focus on the capacitance dependence on the pore size and the curvature of the graphitic carbon electrode; for the lithium-ion battery, we focus on the reactions between the electrolyte and the edge plane of the lithiated graphite.