Sub-micrometer Li₆PS₅Cl regulated cathodic Li kinetics in sulfide based all-solid-state batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state batteries (ASSBs) face challenges in practical application due to poor lithium-ion (Li) kinetics at electrode interfaces.
• Inadequate contact between cathode active materials (CAMs) and solid-state electrolytes (SSEs) limits Li transport sites and overall battery performance.

Purpose of the Study:

• To improve Li kinetics in ASSB cathodes by enhancing the interface between CAMs and SSEs.
• To investigate the effect of sub-micrometer SSE particle size on Li transport and battery performance.

Main Methods:

• Fabrication of cathodes using sub-micrometer Li6PS5Cl (SU-LPSC) particles for high mass loading.
• Analysis of electrode porosity and ion tortuosity to quantify improvements in ionic pathways.
• Electrochemical testing of SU-LPSC-based batteries to evaluate capacity, coulombic efficiency, and cycle life.

Main Results:

• Reduced ion tortuosity from 3.91 to 1.77 due to conformal contacts formed by SU-LPSC particles.
• Significant improvement in apparent Li-ion diffusion coefficient by nearly 65%.
• SU-LPSC cathodes demonstrated good capacity (197.5 mA h g-1), high initial coulombic efficiency (82.4%), and excellent cycle stability (93.4% retention after 200 cycles at 0.5C).

Conclusions:

• Sub-micrometer SSE particle engineering is effective in enhancing Li kinetics and improving the performance of ASSB cathodes.
• The developed SU-LPSC cathodes offer a promising pathway for designing high-energy density ASSBs with improved interfacial properties.
• This research provides valuable insights for optimizing composite cathode structures and advancing ASSB technology.