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Joint Conference
July 17-18, 2017 Chicago, USA
International Conference on
DIAMOND AND CARBON MATERIALS & GRAPHENE AND SEMICONDUCTORS
Volume 6, Issue 6 (Suppl)
J Material Sci Eng, an open access journal
ISSN: 2169-0022
Diamond and Carbon 2017 & Graphene 2017
July 17-18, 2017
J Material Sci Eng 2017, 6:6(Suppl)
DOI: 10.4172/2169-0022-C1-077
Hybrid electrode materials built on vertically aligned carbon nanofibers arrays for high-performance
electrical energy storage
Jun Li, Steven Klankowski, Gaind Pandey
and
James Emery Brown
Kansas State University, USA
T
oday’s high-performance electrochemical energy storage (EES) devices are represented by the high energy capacity
of lithium-ion batteries (LIBs) and the high power and long cycle life of supercapacitors. At present, they are not able
to be integrated into one system due to the distinct electrochemical mechanisms. The performance of the conventional
electrodes is limited by the low electrical conductivity and slow ion diffusion in the electrode materials. In recent studies,
we have demonstrated an effective approach to overcome these two issues using a three-dimensional nanostructured core-
shell architecture consisting of ~100 – 200 nm thick coaxially coated electroactive materials (such as Si, TiO
2
, LiCoO
2
, V
2
O
5
,
and MnO
2
) on a highly conductive nanostructured current collector, i.e. vertically aligned carbon nano fiber arrays. This
hybrid electrode structure allows effectively mitigating the slow Li+ diffusion by shortening the diffusion length in solid
electrode materials. With proper deposition techniques, the shell materials can form secondary mesoporous structures which
further reduce the ion diffusion path length down to ~10 nanometers in solid electrode materials. In addition, it provides
another benefit due to the significant pseudo capacitive contribution associated with fast faradaic reactions at or near the
electrode surface. As a result, these electrodes present the features of a battery-super capacitor hybrid based on Li chemistry.
The EES devices based on such hybrid materials offer high specific energy at very high power rates that are comparable to
supercapacitors. These studies demonstrated the potential for multi-scale nanostructured EES electrodes to achieve stable long
charge-discharge cycles in the super capacitor power regime (i.e. completing charging or discharging in less than 1 min.) while
maintaining the battery-like high energy capacity. Such hybrid structure also significantly improves the mechanical stability of
the electrode materials, particularly for future batteries involving larger ions such as Na
+
and Mg
2+
.
junli@ksu.eduNew class of porous and metal-free electrocatalyst for oxygen reduction reaction by enhanced
amide functionalization on graphene
Mohammad Shamsuddin Ahmed and Young-Bae Kim
Chonnam National University, Republic of Korea
I
n the meantime, considerable effort has been focused to search for sustainable and renewable sources of green and clean
energy because of the increasing demands and environmental impact of traditional energy resources, such as fossil fuels.
Fuel cells (FCs) obtain significant attention as next generation energy sources because of their superior energy conversion
efficiency and potential to provide clean energy. Metal-free electrocatalysts for oxygen reduction reaction (ORR) in FCs are
an interesting research topic due to low cost much stable and tolerance to crossover effect than that of expensive noble metals.
However, a porous graphene catalyst has been prepared with 1,4-diaminobutane (DAB) through amide functionalization,
and has been used as a metal-free electrocatalyst for ORR in alkaline fuel cells. DAB has been used as a junction among
functionalized graphene layers to impart electrocatalytic activity for the ORR resultant from the interlayer charge transfer.
The successful amidation in the process of catalyst preparation have been confirmed. A hierarchical porous structure has also
been confirmed through surface morphological analysis. The BET specific surface area and thermal stability have increased
after successful amide functionalization. The as-prepared catalyst has been proven an efficient metal-free electrocatalyst with
better electrocatalytic activity, stability, and tolerance to crossover effect than commercially available Pt/C for ORR via a direct
four-electron involved pathway. This report will encourage preparing many more carbon-based electrocatalysts for other
electrochemical applications including catalysis and sensing.
suddin_bcsir@yahoo.com