LiI-Doped Sulfide Solid Electrolyte: Enabling a High-Capacity Slurry-Cast Electrode by Low-Temperature Post-Sintering...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state lithium batteries (ASSLBs) using sulfide solid electrolytes (SEs) offer high ionic conductivity, safety, and energy density.
• Practical slurry-cast composite electrodes exhibit limited performance due to poor interfacial stability between active materials and SEs, caused by polymeric binders.

Purpose of the Study:

• To develop a low-temperature post-sintering process for slurry-cast composite electrodes in ASSLBs.
• To overcome the detrimental effects of polymeric binders on electrochemical performance in sulfide-based ASSLBs.

Main Methods:

• Utilized LiI-doped Li3PS4 solid electrolyte for improved ionic conductivity and Li metal compatibility.
• Applied a low-temperature post-sintering technique to composite cathodes (LiNi0.6Co0.2Mn0.2O2, LiI-doped Li3PS4 SE, binder, conducting agent).
• Conducted electrochemical impedance spectroscopy and galvanostatic intermittent titration technique for detailed analysis.

Main Results:

• Post-sintering significantly improved electrochemical performance compared to conventional slurry-cast electrodes with pre-annealed SEs.
• Reduced interfacial resistance at solid-solid interfaces.
• Enhanced chemomechanical robustness of the composite electrodes.

Conclusions:

• The low-temperature post-sintering process effectively mitigates binder-induced issues in slurry-cast composite electrodes.
• This method enables the development of practical and high-performance ASSLBs utilizing sulfide solid electrolytes.