Preparation And Capacitance Performance Of Nanostructured LDH

LDH possess excellent electrochemical performance and have a good application prospective in electrode material for ultracapitors. Nano-sized LDH with different species were prepared. Techniques such as XRD, FT-IR, XPS, cyclic voltammetry, chronopotentiometry, AC impedance were used to study the physical properties and electrochemical performances of the synthesized materials.Nanostructured Co-Ni-Al-CO₃-LDH was synthesized by liquid-phase precipitation with Co(OH)₂, Ni(OH)₂, Al(OH)₃, NaOH and Na₂CO₃ as source materials. Ratio between Ni²⁺, Co²⁺, Al³⁺, OH^- and CO₃^2- is 4: 6: 5: 24: 10(mole). The LDH possesses a specific capacitance of 413 F/g between 0⁰.5V(vs.SCE) in 1mol/L aqueous solution, and does a good cycling performance. Experiment is made at 70℃for 48h,Nanostructured Ni-Co-Ti(Zr)-LDH was synthesized by liquid-phase precipitation with Ni(OH)₂, Co(OH)₂, TiCl₄(ZrCl₄) and carbamide as source materials. Ratio Ni²⁺, Co²⁺, M²⁺ and urea is 4: 1: 1: 53(mole). The LDH possesses a specific capacitance of 507.2(512.7)F/g between 0⁰.5V(vs.SCE) in 1mol/L aqueous solution, and does a good cycling performance. Experiment is made at 90℃for 18h.FT-IR pattern show that using urea as one source in the experiment synthesized LDH, the anions intercalated in the LDH are two. One is CNO^-, and the other is CO₃^2-. The CO₃^2- was obtained when the urea was completely decomposed in the alkaline solution. XPS pattern show that the more negative charge the M⁴⁺ takes, the easier the M⁴⁺ is capable to exchange the M²⁺ which original exist in the frame.