Carbon-based Nanomaterials For Supercapacitor And Electrocatalytic

The energy crisis resulting from rapidly increasing energy consumption and the critical issue of environmental pollution have attracted tremendous attention.The clean,green renewable energy storage and conversion technology is imminent.Among various kinds of energy storage and conversion technologies,the three energy storage technologies of supercapacitor,fuel cell and lithium battery should have great potential.Despite the great progress in recent years,there are still many problems need to solve,such as energy storage equipment in electrode materials of poor electrical conductivity,and electrolyte interface instability leads to its low energy density,such as poor stability problems.This work gives full consideration to the above problems,in order to improving the conductivity and porous mesh structure,we design and synthesis new functional structure of carbon nanomaterial and studies its electrochemical properties and applications.1.We propose a green and efficient strategy by multicomponent surface self-assembly of commercially melamine sponge?CMS?to produce CoOx nanoparticles and surface N-co-doped carbon aerogels?Co-N-CAs?.The CMS is green N precursor and 3D substrate for self-assembly in the strategy.The resulting Co-N-CAs exhibit 3D hierarchical,interconnected macro-and bimodal meso-porosity?6.3nm and<4nm?,high surface area(1383m² g^-1),and highly dispersed,semi-exposured CoOx nanoparticles.Benefiting from these properties,the Co-N-CAs show superior electrocatalytic oxygen reduction?ORR?activities,high specific capacitance?433 F g-1?,excellent lithium storage?938 mAh g-1?,and outstanding durability in terms of a negative shift of only 19 mV after 10 000 cycles.In addition,we get the synthetic nitrogen doped carbon aerogel?NCAs?,with low density?0.001 g cm-3?,large open pores,and high surface area(1626 m² g^-1),using the same multicomponent self-assembly method.The as-prepared NCAs have electrocatalytic oxygen reduction?ORR?activities,high specific capacitance?354 F g-1?,and outstanding durability,retaining approximately 85%of the initial speci fic capacitance even after 10 000 cycles.2.We report a versatile "molecular-confined gelation" route to construct strongly interactional metal oxides and N-C frameworks?C03O4-N-C?with interconnected configuration.Through simply chelating the various transition metal ions with EDTA in agarose hydrogel and subsequently carbonization,the Co₃O₄-N-C can be prepared.The resulting Co₃O₄-N-C frameworks-based OER catalysts,afforded a current density of 10 mA cm 2 at the overpotential of only 339 mV and good stability in 0.1 M KOH.Moreover,the Co₂P-N-C catalysts derived from Co₃O₄-N-C frameworks through a low-temperature phosphidation exhibited excellent HER activity in 1.0M KOH with a low overpotential of 139 mV to reach 10mA cm-2,a small Tafel slope of 45mV dec-1 and impressive stability.