THESIS
2017
xvii, 132 pages : illustrations ; 30 cm
Abstract
Producing electricity from renewable energy sources, as well as developing electric vehicles (EVs), are effective strategies to reduce fossil fuel consumption and suppress global environment issues. To make these happen, attempts have been made either to improve the energy densities of current energy storage devices such as supercapacitors and lithium ion batteries (LIBs), or to develop novel energy storage devices such as sodium ion batteries (SIBs). Among all the efforts have been made, design of advanced electrode materials with a high reversible capacity is a very important approach.
Porous carbon loaded with functional nanoparticles such as metal, metal oxide, or metal sulfide can be used as electrode materials for energy storage devices. In this thesis, a facile one-pot synthesis...[
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Producing electricity from renewable energy sources, as well as developing electric vehicles (EVs), are effective strategies to reduce fossil fuel consumption and suppress global environment issues. To make these happen, attempts have been made either to improve the energy densities of current energy storage devices such as supercapacitors and lithium ion batteries (LIBs), or to develop novel energy storage devices such as sodium ion batteries (SIBs). Among all the efforts have been made, design of advanced electrode materials with a high reversible capacity is a very important approach.
Porous carbon loaded with functional nanoparticles such as metal, metal oxide, or metal sulfide can be used as electrode materials for energy storage devices. In this thesis, a facile one-pot synthesis method has been developed to prepare metal ions embedded colloidal carbon spheres (M-CCSs) from sodium gluconate and a metal salt via hydrothermal treatment. Depending on the interaction between gluconate anions and the metal ions, as-prepared M-CCS can be non-porous or porous. In particular, porous M-CCSs can be easily converted to metal or metal oxide embedded porous carbon spheres by calcination in N
2.
The as-developed synthesis method is first applied to prepare Fe, Co, or Ni nanoparticles embedded porous carbon spheres as electrode materials for supercapacitors. Benefiting from the uniform distribution of metal nanoparticles and the highly porous structure of the carbon matrix, these materials deliver high capacitances and acceptable cyclic performances.
The synthesis method is then used to prepare tin oxide loaded porous carbon spheres as anode materials for LIBs. By a slight modification to the synthesis method, Si doping is introduced. With the presence of the porous carbon matrix and the doped Si, as-generated anode materials exhibit high specific capacities, low irreversible capacity loss, stable cyclability and outstanding rate capability.
Also, the as-developed synthesis method is modified to synthesize iron sulfide embedded porous carbon spheres as anode materials for SIBs. Associated by the carbon matrix, iron sulfide nanoparticles are connected and assembled into porous hollow spheres. Compared to its counterpart without carbon, the as-synthesized anode material show much higher reversible capacity, better cyclability and more reliable rate capability.
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