Construction of Multifunctional Conductive Carbon-Based Cathode Additives for Boosting Li₆PS₅Cl-Based All-Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state lithium batteries (ASSLBs) offer enhanced safety but suffer from solid electrolyte degradation.
• Degradation is often caused by side reactions between solid electrolytes and conductive carbon additives (CCAs) in composite cathodes.
• This degradation leads to insulating byproducts, hindering battery performance.

Purpose of the Study:

• To develop novel CCAs that prevent solid electrolyte degradation in ASSLBs.
• To improve the electrochemical performance and long-term stability of Li6PS5Cl (LPSCl)-based ASSLBs.
• To introduce a "conversion-protection" strategy for unstable composite cathode interfaces.

Main Methods:

• Synthesis of Mo3Ni3N nanosheets embedded onto N-doped porous carbons (NPCs) as CCAs (Mo-Ni@NPCs).
• Incorporation of Mo-Ni@NPCs into LiCoO2 composite cathodes for LPSCl-based ASSLBs.
• In situ surface reconstruction of CCAs to form ultra-stable MoS2-Mo3Ni3N heterostructures.
• Electrochemical performance testing including discharge capacity, Coulombic efficiency, and cycling stability.

Main Results:

• The synthesized Mo-Ni@NPCs effectively suppressed hydroxide group survival and prevented LPSCl decomposition.
• In situ generated MoS2-Mo3Ni3N heterostructures facilitated dual-migration pathways for electrons and Li+ ions.
• ASSLBs with Mo-Ni@NPCs exhibited an ultra-high first discharge capacity of 148.61 mAh g-1 (0.1C).
• The batteries achieved a high Coulombic efficiency of 94.01% and excellent capacity retention of 90.62% after 1000 cycles.

Conclusions:

• The developed Mo-Ni@NPCs act as effective CCAs, enhancing the stability of composite cathodes in ASSLBs.
• The "conversion-protection" strategy successfully mitigates interface instability and promotes ASSLB commercialization.
• This approach offers a promising solution for improving the electrochemical performance and durability of solid-state batteries.