A solid sulfur cathode for aqueous batteries.

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Sulfur's high resistivity and low electroactivity typically preclude its use as a room-temperature battery cathode.
• Conventional battery designs face limitations in achieving high energy density and capacity at ambient temperatures.

Purpose of the Study:

• To overcome the limitations of sulfur as a cathode material for room-temperature batteries.
• To develop a high-capacity elemental sulfur cathode utilizing an aqueous polysulfide interface.
• To evaluate the performance of an aluminum-sulfur battery system.

Main Methods:

• Fabrication of an elemental sulfur cathode.
• Implementation of a lightweight, conductive, aqueous polysulfide interface.
• Electrocatalyzed reaction: S + H(2)O + 2e(-) --> HS(-) + OH(-).
• Assembly and testing of an aluminum-sulfur battery with the novel cathode.

Main Results:

• Achieved a measured capacity exceeding 900 ampere-hours per kilogram for the sulfur cathode, over 90% of theoretical capacity.
• The aluminum-sulfur battery demonstrated a cell potential of 1.3 volts.
• Experimental specific energy reached up to 220 watt-hours per kilogram, with a theoretical potential of 910 watt-hours per kilogram.

Conclusions:

• The developed elemental sulfur cathode, enabled by an aqueous polysulfide interface, significantly enhances sulfur's electroactivity at room temperature.
• Aluminum-sulfur batteries show promise as a high-energy-density storage solution.
• This approach offers a viable pathway for next-generation battery technologies.