Engineering d-p Orbital Hybridization in a Single-Atom-Based Solid-State Electrolyte for Lithium-Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Enhancing ionic conductivity in solid-state composite polymer electrolytes (CPEs) is crucial for battery performance.
• Regulating lithium salt dissociation kinetics via inorganic filler interactions is key, but the role of filler electronic environments is unclear.

Purpose of the Study:

• To investigate the influence of fillers' external electronic environments on lithium salt dissociation dynamics in CPEs.
• To design single-atom sites in metal-organic framework fillers for an electrocatalytic strategy to boost lithium salt dissociation and ionic conductivity.

Main Methods:

• High-throughput density functional theory (DFT) calculations and machine learning to identify a new descriptor (λ) for tuning d-p orbital coupling.
• Incorporation of optimal single-atom (Ti) sites into a ZIF-8 matrix for poly(ethylene oxide) (PEO)-based CPEs.

Main Results:

• Achieved ionic conductivity exceeding 10⁻³ S/cm at 30°C with Ti-ZIF-8/PEO electrolytes.
• Demonstrated robust solid electrolyte interphase formation and compatibility with various high-performance cathodes (LiCoO₂, LNCM, sulfur).
• Solid-state lithium metal batteries showed excellent cycling stability (>5000 cycles) and low-temperature performance (-30°C).

Conclusions:

• Engineering d-p orbital hybridization using single-atom sites in inorganic fillers is a transformative approach for designing highly ion-conductive CPEs.
• The electrocatalytic strategy effectively enhances lithium-ion conductivity and battery performance.
• The developed CPEs show significant promise for advanced solid-state lithium metal batteries.