Enhanced Cycling Performance of High-Voltage Solid-State Lithium Batteries via In Situ Cathode-Electrolyte Interface...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Poly(vinylidene fluoride) (PVDF)-based polymer electrolytes with solvent-Li+ complexes offer fast ion conduction.
• However, these electrolytes show poor compatibility with high-voltage cathodes due to residual solvent effects.

Purpose of the Study:

• To investigate the impact of residual solvent on ion transport and interfacial stability in polymer electrolytes.
• To develop a strategy for enhancing the compatibility of PVDF-based electrolytes with high-voltage cathodes.

Main Methods:

• Computational simulations and experimental analysis were employed.
• Lithium difluorophosphate (LDFP) was introduced as a sacrificial additive in composite cathodes.
• Characterization of the solid-state battery interface and performance evaluation.

Main Results:

• Residual solvent decomposition leads to nonuniform and unstable cathode-electrolyte interphases (CEI) in LiNi0.8Co0.1Mn0.1O2 (NCM)/Li batteries.
• LDFP additive forms a robust, uniform, inorganic-rich CEI layer in situ.
• Passivation of NCM catalytic sites by LDFP adsorption improves interfacial stability.

Conclusions:

• Controlling residual solvent content is crucial for optimizing polymer electrolyte performance.
• LDFP acts as an effective additive for constructing stable CEI layers, enabling long-term cycling in solid-state batteries.