Stable Cycling with Intimate Contacts Enabled by Crystallinity-Controlled PTFE-Based Solvent-Free Cathodes in...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state batteries (ASSBs) with lithium-metal anodes offer high safety and energy density for next-generation devices.
• Cathode volume changes in ASSBs lead to contact loss, poor current distribution, and degraded electrochemical performance.

Purpose of the Study:

• To develop a simple, solvent-free electrode engineering approach for ASSBs.
• To improve interfacial contact and electrochemical properties of cathodes using a novel binder.
• To investigate the role of binder crystallinity on electrode performance.

Main Methods:

• Utilized a solvent-free electrode preparation method with polytetrafluoroethylene (PTFE) as a binder.
• Controlled PTFE crystallinity through heat treatment to enhance mechanical properties.
• Fabricated high-nickel LiNi0.8Mn0.1Co0.1O2 cathodes for ASSBs and conducted electrochemical testing.

Main Results:

• Highly crystalline PTFE demonstrated robust mechanical properties, ensuring intimate contact within the cathode.
• PTFE-modified cathodes exhibited improved cycle stability and rate performance in ASSBs.
• Postmortem analysis confirmed sustained intimate contact and a stable cathode-electrolyte interface during cycling.

Conclusions:

• Controlling PTFE crystallinity via heat treatment is an effective strategy for enhancing ASSB cathode performance.
• The developed solvent-free method ensures stable interfaces and improved electrochemical properties.
• This approach is versatile and applicable to various cathode materials and solid electrolytes in ASSBs.