Unveiling the polysulfide-PPY interaction for enhanced lithium-sulfur battery performance

Author(s)

Chauque, Susana ; Souza, Breno L. ; Sintaku, Heloise M. ; Ando, Romulo A. ; Torresi, Roberto M.

• Document type: Journal article
• Source: Electrochimica Acta; v. 475, p. 12-pg., 2023-12-02.

Abstract

Understanding the processes in lithium-sulfur (Li-S) batteries is critical to advancing this promising energy storage technology. To this end, a 3D polypyrrole-based sponge (PPY) was synthesized as a sulfur host for positive electrodes in (Li-S). Through optimization, the PPY:S8 composite showed interesting electrochemical performance, including a cycle lifetime of over 200 cycles and remarkable specific capacitances at 0.2 A g-1. Electrochemical impedance spectroscopy (EIS) data provided valuable insights. In addition to the unchanged solution resistance indicating a minimal shuttle effect, the capacitance of the PPY film remains robust due to its bipolaronic state and shows strong sulfur retention, especially at the LiPSs/S8 potential. Operando Raman spectroscopy revealed the stability of the bipolaronic state and the "neutralization" of the lithium polysulfides (LiPSs) by the incorporation of sulfur. Moreover, UV-vis analysis confirmed the efficient absorption of LiPS within the PPY matrix. These results highlight the potential of PPY as an effective sulfur host that minimizes the shuttle effect and improves the charge storage capability of Li-S batteries. This research contributes to the development of advanced materials for energy storage systems and highlights the importance of using positively charged materials as carriers for sulfur in Li-S batteries. (AU)

• FAPESP's process: 22/10235-4 - MECHANOCHEMICAL SYNTHESIS OF POROUS ORGANIC STRUCTURES APPLIED TO POSITIVE ELECTRODES OF LITHIUM-SULFUR (Li-S) BATTERIES
• Grantee: Heloise Molinari Sintaku da Silva
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/11320-0 - High performance electrochemical capacitors
• Grantee: Susana Chauque
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/09341-1 - Lithium-sulfur batteries: development of new generation of positive electrodes based on composites of MOFs/sulfur
• Grantee: Breno Luiz de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 21/00675-4 - Tying up materials for electrochemical energy storage and catalysis
• Grantee: Roberto Manuel Torresi
• Support Opportunities: Research Projects - Thematic Grants