Phase-Changeable Dynamic Conformal Electrode/electrolyte Interlayer enabling Pressure-Independent Solid-State Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-metal solid-state batteries (Li-SSBs) offer high energy density but suffer from interfacial degradation under low pressure.
• This degradation leads to poor electrochemical performance in Li-SSBs.

Purpose of the Study:

• To develop a phase-changeable interlayer for Li-SSBs to ensure stable electrode/solid-state electrolyte (SSE) contact.
• To improve the electrochemical performance and interfacial integrity of Li-SSBs without requiring high external pressure.

Main Methods:

• Fabrication of a phase-changeable interlayer with strong adhesive and cohesive properties.
• Characterization of the interlayer's ionic conductivity and its effect on the Li/SSE interface.
• Testing of Li-SSBs with the interlayer under low-pressure conditions.

Main Results:

• The interlayer provides self-adhesive and dynamic conformal contact, resisting up to 1.9 MPa pulling force without external pressure.
• The interlayer exhibits high ionic conductivity (1.3 × 10^-3 S cm^-1) due to optimized Li+ coordination.
• Modified cells show pressure-independent contact impedance over 700 hours and 85% capacity retention after 400 cycles in a LiFePO4 pouch cell at 0.1 MPa.

Conclusions:

• The phase-changeable interlayer effectively resolves interfacial instability in Li-SSBs under low pressure.
• This innovation enables robust, long-lasting Li-SSBs with improved electrochemical performance and self-healing capabilities.