Sacrificial Additive C₆₀-Assisted Catholyte Buffer Layer for Li₁₊AlTi_2-(PO₄)₃-Based All-Solid-State High-Voltage...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state batteries (ASSBs) with high-nickel layered oxide cathodes offer high energy density and safety.
• Interfacial instability between oxide electrolytes and cathodes limits battery lifespan.
• High-nickel cathodes like LiNi0.8Co0.1Mn0.1O2 (NCM811) are prone to degradation.

Purpose of the Study:

• To enhance the electrochemical stability of NCM811 cathodes coupled with Li1.4Al0.4Ti1.6(PO4)3 (LATP) solid-state electrolytes.
• To improve the cycling stability and longevity of high-voltage ASSBs.
• To investigate the role of a sacrificial additive in forming a stable cathode-electrolyte interphase (CEI).

Main Methods:

• Incorporation of a sacrificial additive, C60, into the catholyte buffer layer.
• Fabrication of NCM811/LATP solid-state batteries.
• Electrochemical characterization including charge-discharge cycling and capacity retention analysis.
• Analysis of the CEI composition using surface-sensitive techniques (implied).

Main Results:

• Formation of a uniform and robust CEI film enriched with LiPO2F2, LiPF6, and C60F on NCM811 particles.
• The NCM811/LATP solid-state battery achieved a discharge capacity of 150.3 mAh g-1.
• Excellent cycling stability with 85% capacity retention after 200 cycles at 0.5 C.

Conclusions:

• The addition of C60 effectively stabilizes the cathode-electrolyte interface in high-voltage ASSBs.
• The spontaneously formed CEI layer mitigates interfacial degradation, enhancing battery longevity.
• This approach provides a practical strategy for developing stable LATP-based high-voltage ASSBs.