A high-entropy mixed ionic and electronic conductor for accelerating the cathode dynamics in all solid-state lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Electron and ion transport are critical for cathode dynamics in all solid-state lithium metal batteries (ASSLMBs).
• Conventional composite strategies create challenging solid-state interfaces that impede carrier mobility.
• Developing efficient ionic and electronic conductors is key to advancing ASSLMB technology.

Purpose of the Study:

• To introduce a new high-entropy mixed ionic and electronic conductor (HE-O-MIEC) for ASSLMB cathodes.
• To investigate the electrochemical properties and interfacial compatibility of the HE-O-MIEC.
• To demonstrate the performance enhancement of ASSLMBs utilizing the novel conductor.

Main Methods:

• Synthesis of a high-entropy mixed ionic and electronic conductor (HE-O-MIEC), Li_1/6-x(LaPrNdSrBa)_1/6CoO_3-δ.
• Characterization of electronic and Li⁺ conductivity at room temperature.
• Assembly and electrochemical testing of ASSLMBs with the HE-O-MIEC cathode and Li_6.4La₃Zr_1.4Ta_0.6O₁₂ electrolyte.

Main Results:

• The HE-O-MIEC achieved high electronic conductivity (1150 S/cm) and notable Li⁺ conductivity (2.3 × 10^-4 S/cm).
• Enhanced Li⁺ conductivity was attributed to high configurational entropy, promoting solubility and Li⁺ concentration.
• The ASSLMB demonstrated a 115 mAh/g initial discharge capacity and retained 83% capacity after 500 cycles without external pressure or organic electrolyte.

Conclusions:

• The developed HE-O-MIEC material effectively facilitates homogeneous electron and ion transport in ASSLMBs.
• This material shows promise for improving active material utilization and overcoming interfacial challenges in ceramic-based ASSLMBs.
• The findings highlight the potential of high-entropy materials in next-generation solid-state batteries.