High-Mass-Loading Li-S Batteries Catalytically Activated by Cerium Oxide: Performance and Failure Analysis under Lean...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-energy-density lithium-sulfur (Li-S) batteries face challenges with increasing sulfur mass loading and minimizing electrolyte.
• Previous work identified the potential-limiting step in Li-S batteries under lean electrolyte conditions.

Purpose of the Study:

• To advance the understanding of Li-S batteries by extending previous findings to a new catalyst and high sulfur loading.
• To develop a multifunctional 3D network for enhanced Li-S battery performance.

Main Methods:

• Integration of cerium oxide (CeOx) nanostructures into cotton-derived carbon to create a 3D network.
• Electrochemical testing of the S/CeOx/C electrode at high sulfur loading and low electrolyte/sulfur ratio.
• Analysis of failure mechanisms in Li-S cells under lean electrolyte conditions.

Main Results:

• The S/CeOx/C electrode achieved a stable areal capacity of 9 mAh cm-2 with a high sulfur loading of 14 mg cm-2 at an electrolyte/sulfur ratio of 5 µL mg-1.
• A previously overlooked failure pattern was discovered: local short-circuiting due to lithium dendrite penetration through the separator during charging at high current density.
• The developed material facilitates high active material hosting, electron transport, and catalysis of the sulfur lithiation reaction.

Conclusions:

• The study highlights the critical importance of developing novel material structures for Li-S batteries.
• Understanding and mitigating failure mechanisms, such as lithium dendrite growth under lean electrolyte conditions, is crucial for advancing Li-S battery technology.
• The multifunctional 3D network shows promise for high-performance Li-S batteries.