LiNi_0.6Co_0.2Mn_0.2O₂ Cathode-Solid Electrolyte Interfacial Behavior Characterization Using Novel Method Adopting...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Organic liquid electrolytes in lithium batteries face limitations, driving research towards all-solid-state lithium batteries (ASSLBs).
• High-performance ASSLBs require solid electrolytes (SEs) with superior ionic conductivity and stable interfaces with active materials.

Purpose of the Study:

• To synthesize and characterize a novel, highly ion-conductive argyrodite-type solid electrolyte (Li6PS5Cl).
• To quantitatively analyze the interfaces between the synthesized SE and active materials in ASSLBs.
• To evaluate the electrochemical performance and stability of ASSLBs utilizing the new SE.

Main Methods:

• Synthesis of argyrodite-type Li6PS5Cl solid electrolyte.
• Measurement of ionic conductivity at room temperature.
• Electrochemical testing of a single LiNi0.6Co0.2Mn0.2O2 (NCM622) particle electrode interfaced with Li6PS5Cl.
• Analysis of the solid electrolyte interphase (SEI) layer formation.
• Tafel plot analysis for electrochemical kinetic parameters.

Main Results:

• Achieved high ionic conductivity of 4.8 mS cm-1 at room temperature for Li6PS5Cl.
• Measured an initial discharge capacity of 1.05 nAh for a single NCM622 particle.
• Observed initial irreversibility due to SEI formation, followed by high reversibility and stability in subsequent cycles.
• Tafel plot analysis indicated an increasing conduction barrier and charge transfer resistance with higher discharge currents and depths.

Conclusions:

• The synthesized Li6PS5Cl is a promising solid electrolyte for high-performance ASSLBs.
• Interface analysis and understanding SEI formation are critical for optimizing ASSLB performance.
• Electrochemical kinetic studies reveal insights into conduction barriers affecting battery performance at higher charge/discharge rates.