INTERNATIONAL JOURNAL OF ELECTRIC AND HYBRID VEHICULES
I.J.E.H.V.
contact : b.maisseu@ehcar.net
I.J.E.H.V.
Conferences
Congress - Meeting
Library
News
News Records

02-03-2015

The Scientific Breakthrough That Will Completely Change The Electric Vehicle Market
A highly efficient polysulfide mediator for lithium–sulfur batteries


a) TEM image of ?MnO2 nanosheets and its corresponding selected area electron diffraction pattern, (b) high-resolution TEM image of ?MnO2 nanosheets, (c) SEM image of the ?MnO2 nanosheets, (d) X-ray diffraction pattern of ?MnO2 nanosh…

Research that could make lithium ion batteries obsolete : Scientists at the University of Waterloo in Ontario announced this week that they have made a breakthrough in lithium-sulfur battery technology that could increase an EVs range by 3 times with the same weight and a lower cost. Essentially, sulfur would be a good battery cathode material because, along with increasing energy density, it is abundant, light, and cheap. So finding materials that make the battery's construction possible would be a breakthrough.
Lithium-sulfur technology is far from production, but if it lives up to expectations we could see a Model S with a range of nearly 900 miles or a Nissan Leaf that could go 250 miles on a single charge, without a bigger battery.
The lithium–sulfur battery is receiving intense interest because its theoretical energy density exceeds that of lithium-ion batteries at much lower cost, but practical applications are still hindered by capacity decay caused by the polysulfide shuttle. Here we report a strategy to entrap polysulfides in the cathode that relies on a chemical process, whereby a host—manganese dioxide nanosheets serve as the prototype—reacts with initially formed lithium polysulfides to form surface-bound intermediates. These function as a redox shuttle to catenate and bind ‘higher’ polysulfides, and convert them on reduction to insoluble lithium sulfide via disproportionation. The sulfur/manganese dioxide nanosheet composite with 75?wt% sulfur exhibits a reversible capacity of 1,300?mA?h?g-1 at moderate rates and a fade rate over 2,000 cycles of 0.036%/cycle, among the best reported to date. We furthermore show that this mechanism extends to graphene oxide and suggest it can be employed more widely.
Free loading of the complete paper : A highly efficient polysulfide mediator for lithium–sulfur batteries