Coating Robust Layers on Ni-Rich Cathode Active Materials while Suppressing Cation Mixing for All-Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Incompatibility between sulfide solid electrolytes and Ni-rich cathode active materials (CAMs) hinders all-solid-state lithium-ion battery development.
• Protective layers are crucial for mitigating interfacial reactions and improving battery stability.
• Lithium lanthanum titanate (LLTO) offers chemical stability and ionic conductivity but traditional synthesis requires high temperatures, causing detrimental side effects.

Purpose of the Study:

• To develop a rapid and effective method for creating protective LLTO layers on Ni-rich CAMs.
• To address the challenges of high-temperature synthesis, including agglomeration, secondary phase formation, and cation mixing.
• To improve the performance of all-solid-state lithium-ion batteries by resolving electrolyte-cathode incompatibility.

Main Methods:

• Utilized flash-light sintering (FLS), a rapid sintering technique, to fabricate LLTO protective layers.
• Coated LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) with LLTO.
• Analyzed the structural integrity and chemical composition of the LLTO-coated NCM811 after FLS treatment.

Main Results:

• FLS treatment successfully produced a uniform and pure perovskite LLTO protective layer on NCM811.
• The FLS method minimized cation mixing within the NCM811 cathode active material.
• The LLTO-coated NCM811 exhibited a fully covered dense layer, leading to a high initial capacity and resolving incompatibility issues.

Conclusions:

• Flash-light sintering is a viable rapid technique for fabricating LLTO protective layers on Ni-rich CAMs.
• This method effectively overcomes the limitations of traditional high-temperature sintering.
• The FLS approach offers potential for broader applications in advanced battery materials previously limited by processing temperatures.