Controllable Syntheses Of New Carbon Based 2D Composites For Energy Storage And Conversion

In the past decade,two-dimensional?2D?carbon-based materials,have been attracting attention and interests of many scientists.At present most 2D materials are hard to rational control and precise design with specialized morphologies and tailored properties.In this study,an efficient and universal strategy was proposed for two kinds of 2D materials?graphene and Co?OH?₂ nanosheets?.Being loaded by molecules and polymer,2D materials become functional.The details of synthesis and the application tests for each kind of composites are described as follows:?1?Two-dimensional naphthalene diimide/graphene hybrids?NDI-RGO?have been constructed by a facile self-assembly of naphthalene diimide and graphene.We have successfully immobilized redox-active NDI onto the surface of RGO by?–?interactions and electrostatic interactions.As the cathode material in LIB,the resulting NDI-RGO hybrid showed an obvious improvement in cyclic stability and rate capability.NDI-RGO showed a revisable capacity of 170 mAh g^-1 at a current density of 25 mA g^-1 for 260 cycles and maintained the capacity of53 mAh g^-1 at 800 mA g^-1,superior to most of the previously reported organic cathodes.?2?Through the above method,perylene diimide/graphene hybrids?PDI-RGO?have been constructed by?–?interactions and electrostatic interactions between PDI and RGO.Graphene promotes the fast transferring of charge carriers in the electrode.The ionic interactions and?-?interactions between PDI and RGO can depress the dissolution of PDI in the liquid electrolyte.The wrinkle PDI-RGO can ensure good contact between electrode and electrolyte.The nanohybrid organic electrodes showed an excellent revisable capacity of 168 mAh g^-1 at a current density of 25 mA g^-1 for 100 cycles and maintained the capacity of 52 mAh g^-1 at a high current density of 800 mA g^-1.?3?2D transition metal catelyst with well controlled mesoporous structures using template synthesis had been synthetized.Co?OH?₂nanosheets were used as templates to realize the mesoporous structures of nonprecious metal catalysts.Polyaniline?PANI?was selected as precursors for preparing MCN.Co?OH?₂ nanosheets wrapped in PANI will transformed into 2D nanosheets composed with Co nanoparticles after high-thermal treating under an inert atmosphere.The Co nanoparticles were then removed by acid etching,leaving mesopores within the resultant MCN.We can control the nitrogen content,nitrogen-bonding configurations,porous structures through changing the temperature of high-thermal treatment and the Co?OH?₂/AN ratio.MCN-2-800 showed uniform mesopores,high content of pyridinic N and graphitic N and a highly accessible surface area,resulting in an improvement of oxygen reduction reaction performance?onset potential-0.119 V,and half-wave potential-0.186 V?in alkaline media.