Study On Preparation And Electrochemical Properties Of Carbon Based Composites

With the application of graphene,carbon nanotubes and other materials in electrochemical energy storage,the carbon based materials have attracted more and more attention.Pyrolytic carbon has attracted wide attention as a new kind of electrode material.The superabsorbent particles inside the diaper are used as the basic carbon source to explore the electrochemical performance after pyrolysis.Firstly,a three-dimensional（3D）nitrogen-doped porous carbon（NSAPC-W）nanoarchitecture from used baby diapers has been employed as an anode material for the lithium and sodium ion batteries（LIBs/SIBs）.The NSAPC-W shows the coexistence of meso/micro porous structure as well as the reasonable thickness of carbon layer with thehigh specific surface area employing urine nitrogen source.By inheriting the unique skeleton of the waste diaper,the resultant materialsexhibit excellent ultra-long cycling performance as well as great rate performance for lithium and sodium ion shuttling.Tested against Li,the electrode of NSAPC-W exhibits a high specific discharge capacity(941mAh g^-1 at the current of 100 mA g^-1,after 150 cycles),long life span(a specific discharge capacity of 469 mAh g^-1,after 1000 cycles at 2000 mA g^-1current densities).Furthermore,for SIB applications,NSAPC-W offers agood gravimetric capacity(330 mAh g^-1at 100 mA g^-1 after 300 cycles),superior long life cycle(a specific discharge capacity of 187 mAh g^-1,after4000 cycles at current densities of 2000 mA g^-1).The high electrochemical performance of the NSAPC-W can be mainly attributed to the high nitrogen doped3D porous carbon matrix and the carbon wall of reasonable thickness for accommodating a large number of Li⁺/Na⁺ions.Secondly,the three-dimensional（3D）porous composites decorated with NiO and tiny Ni nanoparticles（NNSC）have been preparedvia afacile dissolving-freeze drying and subsequent annealing reactions by using the super absorbent polymer from baby diaper.Then,NNSC electrode can exhibit the high specific capacity and excellent cycle performance as anode materials for LIBs.And more importantly,adopting the carbon matrix derived from baby-diaper offers an interesting approach for next energy storage materials.Last but not least,hard carbon and transition metal oxides attract myriad interest as anodematerials for high-energy rechargeable batteries due to their low costs and high theoretical capacities;practically,they deliver unsatisfactory performance due to their intrinsically microarchitecture.In this work,a facile catalyzed strategy for general synthesis of carbon nanosheet frameworks decorated with nickel nanographitic domains that takes advantage of the adsorption effect of carboxyl and Ni²⁺in hydrogel from superabsorbent polymer and occurs carbon conversion from sp³ to sp² is reported.Such architecture provides a promising structural platform for the fabrication of carbon nanosheet frameworks functionalized with hollow nickel oxide or microporous hollow carbon embedded with expanded nanographite through subsequent chemical conversion.The structures of Ni@G/C impart intimate structural connectivities,speedyly opened freeway for ionic diffusion,large accessible specific surface area,as well as high structural stability,opening up a wide horizon for superior lithium/sodium ion batteries,along with fast kinetics and long cycle life.To summarize,we employed a facile and scalable process to construct a unique carbon framework from SAPs.The superior electrochemical performance is attributed to the 3D porous structure deriving from the diaper,which provides a short Li⁺or Na⁺ions diffusion distance,effective strain relaxation,and large active contact area.Predictably,carbonized products from waste diaper will be a kind of doping porous material and may be also applied to energy storage such as supercapacitor and catalyst supports.