C-S@PANI composite with a polymer spherical network structure for high performance lithium-sulfur batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from poor cycling stability and low conductivity.
• Dissolution and migration of lithium polysulfides lead to capacity fading and low coulombic efficiency.

Purpose of the Study:

• To design and synthesize a novel C-S@PANI composite cathode material for improved Li-S battery performance.
• To enhance the electrochemical properties, particularly low-temperature performance and cycling stability.

Main Methods:

• A simple processing approach involving self-assembly and grafting of polyaniline (PANI) onto oxidized carbon black.
• Encapsulation of elemental sulfur within the PANI hollow spherical network to form the C-S@PANI composite.
• Electrochemical characterization of the composite as a cathode material for Li-S batteries.

Main Results:

• The C-S@PANI composite achieved a high specific capacity of 1453 mA h g⁻¹ at 0.1 C.
• Stable cycling performance with 948 mA h g⁻¹ retained after 200 cycles.
• Demonstrated high capacities of 922 mA h g⁻¹ at 50 °C and 581 mA h g⁻¹ at 0 °C after 200 cycles.

Conclusions:

• The conductive PANI spherical network facilitates dual conduction of Li⁺ and electrons, improving active material utilization.
• The composite structure effectively inhibits polysulfide shuttling, enhancing cycling stability and coulombic efficiency.
• The C-S@PANI composite shows promising electrochemical properties for advanced Li-S batteries, especially at low temperatures.