Engineering Detrimental Functional Groups in Conductive Additives Toward High-Performance All-Solid-State Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Conductive additives are crucial for composite cathodes in all-solid-state lithium batteries (ASSLBs).
• Interfacial side reactions between conductive additives and sulfide electrolytes impede ion transport and degrade battery performance.
• Surface oxygen functional groups on additives often exacerbate these detrimental reactions.

Purpose of the Study:

• To develop a method for modifying conductive additives to mitigate interfacial side reactions in ASSLBs.
• To investigate the impact of surface modification on the electrochemical performance of Super P conductive additive.
• To enhance the utilization of active materials and improve the stability of ASSLBs.

Main Methods:

• A simple hydrogen thermal reduction process was employed to treat Super P conductive additive.
• Characterization of the modified Super P to confirm removal of surface oxygen functional groups.
• Fabrication and electrochemical testing of ASSLBs using reduced Super P in the composite cathode.

Main Results:

• Reduced Super P effectively removed surface oxygen functional groups, weakening interfacial side reactions with sulfide electrolytes.
• ASSLBs incorporating 1 wt% reduced Super P achieved a capacity of 180.2 mAh g⁻¹, compared to 130.8 mAh g⁻¹ with untreated Super P.
• Capacity retention improved significantly to 81.8% with reduced Super P, versus 64.6% for untreated Super P.
• Reduced Super P demonstrated superior performance over reduced carbon nanofiber, attributed to a more complete conductive network.

Conclusions:

• Surface oxygen functional groups on conductive additives play a critical role in interfacial stability in ASSLBs.
• Hydrogen thermal reduction is an effective low-cost strategy to enhance the performance of conductive additives like Super P.
• This approach offers a promising pathway for developing practical and high-performance all-solid-state lithium batteries.