Amorphous AlOCl Compounds Enabling Nanocrystalline LiCl with Abnormally High Ionic Conductivity

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Lithium chloride (LiCl) is a potential solid electrolyte but requires enhanced ionic conductivity.
• Aliovalent doping improves LiCl conductivity but compromises stability and cost.
• Heterogeneous structures offer a new approach to electrolyte design.

Purpose of the Study:

• To develop a novel solid electrolyte with enhanced ionic conductivity and electrochemical stability.
• To investigate the effect of embedding nanocrystalline LiCl in amorphous AlOCl.
• To assess the performance of the new material in all-solid-state batteries.

Main Methods:

• Fabrication of nanocrystalline LiCl embedded in amorphous AlOCl (AlOCl-nanoLiCl).
• Characterization of ionic conductivity, oxidative stability, cost, and mechanical properties.
• Assembly and testing of all-solid-state batteries using AlOCl-nanoLiCl and Li-rich cathodes.

Main Results:

• AlOCl-nanoLiCl achieved an ionic conductivity of 1.02 mS cm^-1, a five-order-of-magnitude increase over LiCl.
• The material demonstrated high oxidative stability, low cost ($19.87 kg^-1), and low Young's modulus (2-3 GPa).
• All-solid-state batteries showed over 1000 cycles of stable performance with Li-rich cathodes.

Conclusions:

• Embedding nanocrystalline LiCl in amorphous AlOCl is an effective strategy to boost ionic conductivity.
• The AlOCl-nanoLiCl composite offers a promising, stable, and cost-effective solid electrolyte for next-generation batteries.
• This approach overcomes limitations of traditional aliovalent doping in LiCl.