3. Sulfur in Rechargeable Batteries
With an operating voltage range of 2.1 Volts (V) and
a theoretical capacity of 1675 milliamp hours per gram
(mAh g@1
), sulfur (when combined with lithium) is superior
in terms of safety and cost to other battery cathode materials
currently being used in commercial applications.
[30] These
facts, along with its semiconducting character and incredible
abundance, have made sulfur a popular research focus for
improving batteries. When combined with the Group 1
elements lithium or sodium, sulfur can be used to make
batteries with desirable properties. Lithium-sulfur (Li-S)
batteries, which have been known since the 1960s,
[31] have
the potential to replace the prevalent lithium ion (Li+
)
batteries which are used today in numerous devices including
laptops, cell phones, and other portable display electronics.
Sodium-sulfur (Na-S) batteries have also been studied for
several decades and were once poised to become the industry
standard for use in numerous applications.
[32] Although
popularity in Na-S batteries decreased for several years
because they were deemed too dangerous for broad use, some
advances in technology and in fundamental understanding
have spurred renewed interest in Na-S batteries for certain
applications.
[33] This section focuses on Li-S and Na-S
batteries, highlighting sulfurQs increasingly important role in
research on rechargeable batteries.