Controllably Assemble And Study On Electrochemical Properties Of LDH-NS/GO-NS

This project is based on a layered compound based on cobalt and nickel.It is synthesized by a exfoliating-recombination strategy for renewable energy conversion and storage materials(OER catalysts,supercapacitors),and is developed by adjusting the crystal structure and electronic structure of the material.Design nanocomposites with high activity capacity and superior performance.This topic has mainly completed the following aspects of research work:This chapter proposes a strategy to design and construct a novel tiling/standing nano-array structure with active sites.Electrocatalytic OER performance test results show that the NiAl-LDH/RGO-5(NG-5)nanocomposite has a lattice unit containing LDH-NS,which has no structure on GO-NS and has excellent electrocatalytic performance.It has a low overpotential of 180 mV at current.The density is 50 mA/cm~2 and the low initial potential is 1.345 V(vs.RHE).In addition,the current density of NG-5 composite(591mA/cm~2)is higher than that of pure NiAl-LDH(123 mA/cm~2)and the potential is 1.7 V(relative to RHE).In addition,the NG-5 composite exhibited excellent long-term electrochemical stability,which remained at 95.28%at 10.0 h,and a longer i-t test(25 h)showed very good stability.At a scan rate of 5 mV/s,the specific capacitance of Ni-Al LDH/RGO-5.6 composites shows a maximum value(1,743.0 F/g)compared to other materials,and a longer discharge time(800.0 s,1.0 A/g),corresponding to C_g of 1,860.0 F/g.This chapter proposes an efficient,convenient and environmentally friendly solid phase exfoliating(SPE)technology that achieves complete exfoliating of Co-Al LDH and GO for ideal storage for several months.In addition,this may be a general method suitable for 2D material exfoliating.The adjustment of Co-Al LDH-NS/GO-NS assembly structure under controlled conditions was studied,and the theoretical structure model was established and further verified by various characterization techniques.The Co-Al LDH/RGO material(Co-Al LDH/RGO-3)with a mass ratio of 3:1 has an ideal tiling structure with the best capacitive performance and a specific capacitance of 1,492 F/g.At a current density of 1.0A/g,after 5,000 cycles,the capacitance retention was 94.3%.In addition,under the two-electrode test system,an energy density of 44.6 Wh/kg can be obtained at a power density of 799.6 W/kg,indicating that the solid phase exfoliating technique presents a bright prospect in the energy application of two-dimensional materials.Under the SPE strategy,the GO and CoCo LDH were successfully stripped into ultra-thin nanosheets with defects and multiple vacancies.Compared with traditional liquid phase exfoliating(LPE),solid phase exfoliating is a kind of cleaning.The time-saving,non-toxic method has a wide range of uses,avoids the adsorption of solvent molecules,and can achieve long-term stable storage of a single layer.Therefore,ultra-efficient exfoliating with solid phase function is compatible with most industrial equipment processing.After series OER performance tests,the overpotentials of CR-4 nanocomposites at current densities of 10 mA/cm~2 is 211 mV,respectively.The corresponding Tafel slope is 87 mV/dec,and it shows excellent OER electrocatalytic performance.