1 research outputs found
Freeze-Dried Sulfur–Graphene Oxide–Carbon Nanotube Nanocomposite for High Sulfur-Loading Lithium/Sulfur Cells
The
ambient-temperature rechargeable lithium/sulfur (Li/S) cell
is a strong candidate for the beyond lithium ion cell since significant
progress on developing advanced sulfur electrodes with high sulfur
loading has been made. Here we report on a new sulfur electrode active
material consisting of a cetyltrimethylammonium bromide-modified sulfur–graphene
oxide–carbon nanotube (S-GO-CTA-CNT) nanocomposite prepared
by freeze-drying. We show the real-time formation of nanocrystalline
lithium sulfide (Li<sub>2</sub>S) at the interface between the S-GO-CTA-CNT
nanocomposite and the liquid electrolyte by in situ TEM observation
of the reaction. The combination of GO and CNT helps to maintain the
structural integrity of the S-GO-CTA-CNT nanocomposite during lithiation/delithiation.
A high S loading (11.1 mgS/cm<sup>2</sup>, 75% S) S-GO-CTA-CNT electrode
was successfully prepared using a three-dimensional structured Al
foam as a substrate and showed good S utilization (1128 mAh/g S corresponding
to 12.5 mAh/cm<sup>2</sup>), even with a very low electrolyte to sulfur
weight ratio of 4. Moreover, it was demonstrated that the ionic liquid
in the electrolyte improves the Coulombic efficiency and stabilizes
the morphology of the Li metal anode