The Structures And Electrochemical Properties Of Nonstoichiometric Titanium Carbide-derived Carbons

Carbide derived carbon (CDC) is a large family of carbon materials derived fromcarbide precursors that are produced by selective etching of metal or non-metal atomsfrom a carbide crystal lattice via halogenations process. CDC enables a wide range ofapplications. In particular，as the application of CDC in supercapacitors, differentstructures of CDC own different electrochemical performance. It is further found thatvolumetric concentration of carbon atoms in carbide precursor has much influence onCDC microstructure. In this paper，nonstoichiometric titanium carbide was synthesized byball-milling the mixed powders of TiC and Ti. Then the precursor was chlorinated at600,800,1000oC to synthesis TiCx-CDC with designed carbon structure and idealelectrochemical performance. Furthermore, chemical intercalation oxidation method wasused for TiCx-CDC to improve electrochemical performance.Two different techniques were used to probe into the structure of TiCx-CDC: X-raydiffraction and Raman spectroscopy. It is found that the degree of order of TiCx-CDC isgradually higher following x ranging from1to0.56.Electrochemic investigation of produced TiCx-CDC was carried out in threeelectrode system. TiCx-CDC was characterized by cyclic voltammetry andelectrochemical impedance spectroscopy in both KOH and H2SO4electrolyte. It is foundthat the specific capacitance of TiCx-CDC became worse with x ranging from1to0.56and the best performance is142.2F/g.The specific capacitance of TiC0.71-CDC is increased after chemical intercalationoxidation in both KOH and H2SO4electrolyte and the maximum of specific capacitance is222.8F/g; The specific capacitance of TiC0.56-CDC increases in H2SO4electrolyte butdecreases in KOH electrolyte after chemical intercalation oxidation and the maximum ofspecific capacitance is221.7F/g.