Woo Young Yoon

Fabrication and characterization of a silicon-carbon nanocomposite material by pyrolysis for lithium secondary batteries

This paper presents the fabrication and testing results of a Silicon-Carbon nanocomposite material used for lithium secondary batteries which was prepared through the pyrolysis of alginic acid which was utilized as the carbon source. Silicon nanoparticles were mixed with alginic acid which was first dissolved in a Na2CO3 solution. After drying, the blend was ground into powders and heated in an argon atmosphere. Based on Raman spectra, the ordering of the carbon from the decomposition of the carbon source was clearly distinguished. The reversible specific discharge capacity of silicon in the electrode of this composite material was as high as 1928 mAhg−1, which indicates excellent cycling stability.

Catalytic behavior of V2O5 in rechargeable Li–O2 batteries

The possibility of using vanadium pentoxide (V2O5) as a catalyst in rechargeable lithium–oxygen (Li–O2) batteries was studied. A V2O5-carbon composite was cast onto Ni foam to form a cathode. Electrochemical cells designed based on the flat cell manufactured by Hohsen Corporation were fabricated. The initial discharge capacity was 715 mAxa0hxa0g−1, and the maximum discharge capacity reached 2,260 mAxa0hxa0g−1 during the twelfth cycle. The cell had high capacity retention during cycling (1.24xa0% during cycles 2–8). V2O5 acted as a catalyst as well as an active material, improving the specific capacity and capacity retention of the non-aqueous Li–O2 cell more effectively than do other materials.