Ether-Based Gel Polymer Electrolyte for High-Voltage Potassium Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Low-concentration ether electrolytes in potassium-ion batteries (PIBs) suffer from poor oxidation resistance and interface stability at high voltages.
• Electrolyte decomposition and ineffective electrode-electrolyte interphase formation limit the performance and lifespan of high-voltage PIBs.

Purpose of the Study:

• To enhance the high-voltage stability and electrochemical performance of PIBs using a novel gel polymer electrolyte (GPE).
• To investigate the role of a sandwich structure-like GPE in forming a stable interface and maintaining ionic transport.
• To suppress aluminum current collector corrosion under high voltage conditions.

Main Methods:

• Development of a sandwich structure-like gel polymer electrolyte (GPE).
• Electrochemical characterization of the GPE in K||graphite and K||FeFe-Prussian blue cells.
• Evaluation of cycling stability, capacity retention, and Coulombic efficiency at high voltage.

Main Results:

• The designed GPE demonstrated a wide electrochemical window and excellent electrochemical performance.
• K||graphite cells achieved 450 cycles with 91% capacity retention.
• K||FeFe-Prussian blue cells (2-4.2 V) showed 99.9% average Coulombic efficiency over 2200 cycles.

Conclusions:

• The sandwich structure-like GPE effectively enhances high-voltage stability and cycling performance in PIBs.
• The GPE facilitates stable interface formation and ionic transport while suppressing Al corrosion.
• This GPE approach offers a promising strategy for developing high-voltage, long-lasting ether-based PIBs.