http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
An electrochemical approach to graphene oxide coated sulfur for long cycle life
Moon, Joonhee,Park, Jungjin,Jeon, Cheolho,Lee, Jouhahn,Jo, Insu,Yu, Seung-Ho,Cho, Sung-Pyo,Sung, Yung-Eun,Hong, Byung Hee The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.31
<P>Owing to the possibilities of achieving high theoretical energy density and gravimetric capacity, sulfur has been considered as a promising cathode material for rechargeable lithium batteries. However, sulfur shows rapid capacity fading due to the irreversible loss of soluble polysulfides and the decrease in active sites needed for conducting agents. Furthermore, the low electrical conductivity of sulfur hampers the full utilization of active materials. Here we report that graphene oxide coated sulfur composites (GO-S/CB) exhibit improved electrochemical stability as well as enhanced rate performance, evidenced by various electrochemical analyses. The cyclic voltammetry and the galvanostatic cycling analysis revealed that the GO plays key roles in homogenizing the nanocomposite structures of the electrodes, in improving the electrochemical contact, and in minimizing the loss of soluble polysulfide intermediates. An electrochemical impedance spectroscopy analysis also confirms the enhanced structural stability of the GO-S/CB composites after battery operation. As a result, the GO-S/CB exhibited excellent cycle stability and specific capacity as high as ???723.7 mA h g(-1) even after 100 cycles at 0.5 C.</P>
Hierarchical carbon-silicon nanowire heterostructures for the hydrogen evolution reaction
Moon, Joonhee,Sim, Uk,Kim, Dong Jin,Ahn, Hyo-Yong,An, Junghyun,Ha, Heonjin,Choi, Kyoung Soon,Jeon, Cheolho,Lee, Jouhahn,Nam, Ki Tae,Hong, Byung Hee The Royal Society of Chemistry 2018 Nanoscale Vol.10 No.29
<P>Silicon nanowires (SiNWs) opened up exciting possibilities in a variety of research fields due to their unique anisotropic morphologies, facile tuning capabilities, and accessible fabrication methods. The SiNW-based photoelectrochemical (PEC) conversion has recently been known to provide an efficiency superior to that of various photo-responsive semiconductor heterostructures. However, a challenge still remains in designing optimum structures to minimize photo-oxidation and photo-corrosion of the Si surface in a liquid electrolyte. Here, we report a simple method to synthesize hierarchically branched carbon nanowires (CNWs) on SiNWs utilizing copper vapor as the catalyst in a chemical vapor deposition (CVD) process, which exhibits outstanding photocatalytic activities for hydrogen generation along with excellent chemical stability against oxidation and corrosion. Thus, we believe that the CNW-SiNW photoelectrodes would provide a new route to developing high-performing cost-effective catalysts essential for advanced energy conversion and storage technologies.</P>