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19XV International Symposium on Self-Propagating High-Temperature Synthesis
SOLUTION COMBUSTION SYNTHESIS OF CARBON-BASED POROUS NANOMATERIALS FOR EFFICIENT ELECTROCHEMICAL APPLICATIONS
P. W. Chen*", C. X. Xu"'b, K. Y. Liu", and X. Gaoac
aState Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081 China
bAerospace Institute of Advanced Materials & Processing Technology, Beijing, 100074 China cInstitute of Pulsed Power Science, Kumamoto University, Kumamoto, 8608555 Japan *e-mail: pwchen@bit.edu.cn
DOI: 10.24411/9999-0014A-2019-10030
Fabricating advanced functional material for excellent energy conversion and storage performance has great importance for solving global energy issues. Porous materials are an ideal choice to improve the mass transport and interface charge transfer in energy devices such as Li-ion batteries and fuel cell, owing to their large surface area and abundant channels. On the other hand, carbon is recognized as a leading electrode material of the above-mentioned applications. Therefore, it is of great interest to develop novel and efficient synthesis strategies to produce porous carbon-based functional materials. Solution combustion is an exciting phenomenon, which involves propagation of self-sustained exothermic reactions along an aqueous or sol-gel media and allows for the synthesis of a variety of nanoscale materials. Through solution combustion method, the reactions of the reductant liquid and oxidant additive was utilized as energy source and carbon source for the formation of different carbon-based porous nanomaterials. These as-prepared nanomaterials were characterized via various techniques, exhibiting different outstanding electrochemical properties and high potential applications in Li-ion battery. Firstly, N-doped carbon nanofoam (Fig. 1a) was synthesized via the combustion of hydrazine hydrate (N2H4H2O) absorbing carbon dioxide (CO2) and magnesium powder. Firstly, the dry ice was added into hydrazine hydrate to form NH2NHCOO-ions as reductant, carbon source and nitrogen source. Subsequently, the magnesium powder was added into the solvent and ignited via a tungsten heating wire. After combustion, the products were recovered and characterized to be N-doped carbon nanofoam, exhibiting efficient electrochemistry performance toward Li-ion battery and oxygen reduction reaction. Moreover, N-doped carbon nanomesh sheets (Fig. 1b) were synthesized through the combustion of ethanol amine absorbing CO2 and magnesium powder along the same procedure. The as-prepared N-doped carbon nanomesh sheets with well-formed one- to four-atom-thick sheet structure possess multiple outstanding properties, such as superior half-wave potential (0.81 V vs RHE), stable oxygen reduction reaction in alkaline medium.
Secondly, using glucose (C6H12O6) and copper nitrate (Cu(NO3)2) as fuel and oxidizing agent respectively, CuO/Cu2O/C composites (Fig. 2a) with different carbon contents were prepared by the solution combustion synthesis method. The as-obtained CuO/Cu2O nanoparticles exhibit uniform spherical morphology and were well distributed in the in-situ synthesized carbon with a content ranging from 3-36 wt %. An anode for Li-ion battery was prepared using this CuO/Cu2O/C composite for the investigation of its electrochemical performance via various techniques. The results reveal its high potential applications with multiple properties, such as > 400 mAh/g capacity at 20 mA g-1 current density and highly stable cycling performance with capacity 260 mA h g-1 after 600 cycles at a current density 0.2 A g-1. This performance is attributed to the synergistic effect of anodes porous structure, conducting carbon coating and two-component CuO/Cu2O structure.
iSHS 2019 Moscow, Russia
(a) (b)
Fig. 1. TEM images of solution combustion synthesized (a) N-doped carbon nanofoam and (b) N-doped carbon nanomesh sheets.
(a) (b)
Fig. 2. (a) SEM image and (b) TEM image of as-obtained CuO/Cu2O/C composites.
Our studies introduce a general solution that can further integrate various additives dissolved homogeneously, thus opening a new avenue of constructing carbon-based functional materials with controlled morphology and modified electrochemical properties.
