A Bifunctional Carbon-Coated Separator for Lithium-Sulfur Cells and Methods of Making the Same

Physical Sciences : Materials and Compounds

Available for licensing


  • Arumugam Manthiram, Ph.D. , Mechanical Engineering
  • Sheng-Heng Chung , University of Texas at Austin

Background/unmet need

Sulfur is appealing as a high-capacity cathode for rechargeable lithium batteries. However, the  commercialization of lithium-sulfur batteries is hampered by fast capacity fade during both dynamic cell cycling and static cell resting. The poor electrochemical stability is due to the polysulfide diffusion, leading to a short cycle life and server self-discharge.

To address these issues, current lithium-sulfur technology has focused on improving the electrical conductivity of the cathode and localizing the active material within the cathode region of the cell by synthesizing "composite" sulfur cathodes or applying novel cell configuration modifications.

Invention Description

Researchers at The University of Texas at Austin have presented the design of a bifunctional separator that integrates two necessary components already inside the cell. With no extra additives, this bifunctional separator allows the use of pure sulfur cathodes involving no complex composite synthesis process, provides a high initial discharge capacity with excellent dynamic stability, and facilitates a high reversible capacity with long cycle life.

This also overcomes the drawbacks of the low sulfur content issue of the composite cathodes and the added significant weight of the free-standing components employed in cell modifications.


  • Excellent cell performance
  • Overcomes the drawbacks of reducing the overall energy density
  • Low cost
  • Time efficient
  • No extra additives and no toxic treatment


  • Use of pure sulfur cathode with excellent dynamic electrochemical stability
  • Low self-discharge rate and outstanding static electrochemical stability

Market potential/applications

Companies involved with lithium-ion batteries, lithium-sulfur batteries, and electrochemical energy storage systems for grid energy storage.

Development Stage

Lab/bench prototype