With the rapid increase of energy demand and the depletion of fossil fuel reserves, research on new environment-friendly energy sources has attracted increasing attention in the past decades. As important hybrid nano-materials for energy storage and conversion, carbon-based nano-composites often exhibit fascinating synergistic effect compared to their singular components. In this study, we successfully developed convenient methods to synthesize various nano-composites with designed carbon architecture, including two dimensional (2D) graphene support and three dimensional (3D) carbon framework, which show excellent performance on energy storage and conversion. 2D graphene supported nano- and subnano-materials, including defect-rich Ni3FeN nanocrystals (NC), MnxPdy NCs, Pt single atoms and Pt atom dimer, were synthesized and studied as catalysts for energy conversion. Besides, we have successfully developed convenient and straightforward methods to prepare of novel nitrogen-doped few-layered graphene-wrapped TiO2 hierarchical porous hybrid nanosheets (TiO2@NFG HPHNSs) and MnO@Mn3O4 core@shell NCs embedded in 3D N-doped carbon frameworks (MnO@Mn3O4/NPCFs), which were used as anode materials for Sodium-ion and Lithium-ion batteries, respectively. These carbon-based nano-composites were determined by conducting high resolution transmission electron microscopy (HRTEM), high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), 3D reconstruction technique and electron energy loss spectroscopy (EELS) valence-state analyses. Theoretical calculations were also carried out to interpreter the properties enhancement during reaction process. Moreover, Aberration corrected TEM was also adopted to in-situ study the atomic scale nucleation and growth behavior of NCs on carbon support. The process of nucleation was directly observed. We also found that the preferential growth facets changed at various growth stages. Our work will facilitate the accurate design of the carbon-based nano-composites and motivate the rational creation of novel composite structures on energy storage and conversion.

Carbon-based nano-composites for energy storage and conversion: Architecture design and in-situ synthesis

256th National Meeting (2018)

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