am8b08438_si_001.pdf (2.04 MB)
Systematic Exploration of the Role of a Modified Layer on the Separator in the Electrochemistry of Lithium–Sulfur Batteries
journal contribution
posted on 2018-08-10, 00:00 authored by Wenzhi Tian, Baojuan Xi, Hongzhi Mao, Junhao Zhang, Jinkui Feng, Shenglin XiongAs
a significant constituent of lithium–sulfur batteries,
the separator also exerts a considerable effect on the performance
of the sulfur cathode. In our work, the mixture of acetylene black
and multiwalled carbon nanotubes is uniformly applied onto the commercial
polypropylene membranes to attain the modified separators. While investigating
different samples, the underlying influence of the coating layer is
systematically scrutinized on the electrochemical behaviors of sulfur
cathodes, relying on the extensive electrochemical and structural
measurements. During the charge/discharge process, the coating layer
can function as the second current collector and drastically contribute
to the improved lithium ions diffusion, determining the electrochemical
kinetics of sulfur-involved reactions. Moreover, it is found that
the thicker the layer, the faster the lithium ions diffuse. It should
be noted that the coating layer also plays a role of the second sulfur
reservoir to endow the ample active sites for sulfur and polysulfides,
which is directly witnessed for the first time. Because of the positiveness
and effectiveness of the modified layer on separators, the sulfur
cathode can offer the superior cycling and rate performance to that
with the original separator.