활성탄과 리튬이차전지용 양극활물질 Li[Ni1/3Co1/3Mn1/3]O2을 사용한 하이브리드 커패시터 연구

Abstract

Nowadays, the research on the electrochemical capacitors aim to increase power and energy density and decrease fabrication costs and at the same time focus on making eco-friendly materials. Compared with the traditional electrochemical double-layer capacitor (EDLC), the hybrid electrochemical supercapacitor which has two different electrode materials shows a higher energy density. The new type of hybrid electrochemical supercapacitors are different from either the EDLCs or the lithium-ion batteries. In the hybrid electrochemical supercapacitors, the negative electrode utilizes a reversible nonfaradaic reaction of cation on the surface of an activated carbon. The positive electrode stores charge through a reversible faradaic reaction of lithium-ion intercalation/deintercalation in a nano-size compound. Some positive electrode materials for lithium-ion batteries show a very high energy density, for example, Li[Ni1/3Co1/3Mn1/3]O2, Li[Ni1/2Mn1/2]O2, Li[Ni0..8Co0.1Mn0.1]O2, etc. In this work, Li[Ni1/3Co1/3Mn1/3]O2 materials as positive electrode for hybrid electrochemical supercapacitors were synthesized by carbonate co-precipitation method. Those materials were combined with an activated carbon as negative electrode to fabricated a hybrid electrochemical supercapacitor. Electrochemical properties of Hybrid electrochemical supercapacitor using Li[Ni1/3Co1/3Mn1/3]O2 as positive electrode was characterized by X-ray diffraction, scanning electron microscope, galvanostatic charge/discharge test, self-discharge test, leakage current test, cyclic voltammetry and impedance analyzer. The Activated carbon/Li[Ni1/3Co1/3Mn1/3]O2 cell, cycled between 0.2 and 2.2V at 1.6A/g based on cathode weight.