Research On Layered Double Hydroxide Materials And Its Application In Capacitance

Layered double hydroxides(LDH)are the materials of hydrotalcite compounds(HT)and hydrotalcite-like compounds(HTLcs).LDH are series of layered compounds composed of brucite samples with positive potential.LDH has attracted more and more attention due to its excellent electrochemical properties.In this work,the layered double hydroxides derived from MOF were synthesized,and applied in capacitance.There are works:(?)Synthesis of LDH with hollow core-shell structure.The MOF was synthesized by CO and PVP,which was used as the sacrificial template for the synthesis of LDH.Besides,the influencing factors of the spatial morphology of LDH were explored.Finally,a regular and ultra-thin prismatic core-shell Co-Fe-LDH was successfully synthesized.TEM images clearly show LDH retains the regular microstructure of MOF materials.(?)The Co-Fe-LDH was used as the electrode active material of supercapacitor.On the one hand,the regular nanostructures of MOF materials are retained,and on the other hand,the hollow structure improves the specific surface area of LDH.BET result shows that LDH has a higher surface area(362.9m~2/g)than MOF(117.5m~2/g).CV experiment shows that the specific capacitance of LDH material reaches 489F/g.the specific capacitance can still maintain more than 95% after 2000 cycle stability tests.(?)Application of LDH in capacitive deionization.The desalting experiment shows that the adsorption capacity of Co-Fe-LDH was 34.2mg/g in 600mg/L NaCl solution under1.2V applied voltage,which is 2.5 times higher than that of traditional carbon materials.The hollow structure Co-Fe-LDH synthesized in this work can significantly improve the desalination capacity.So it may have a broad development prospect in the field of capacitive deionization.