Reducing interfacial resistance of a Li_1.5Al_0.5Ge_1.5(PO₄)₃ solid electrolyte/electrode interface by polymer...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-state Batteries

Background:

• High interfacial resistance at the electrode/electrolyte junction is a major obstacle for all-solid-state lithium batteries (ASSLBs).
• Existing solid-state electrolytes (SSEs) often suffer from poor contact and side reactions, limiting battery efficiency.

Purpose of the Study:

• To decrease the interfacial resistance in ASSLBs using poly(propylene carbonate)-based solid polymer electrolytes (PPC-SPEs) as interlayers.
• To analyze the impact of PPC-SPE interlayers on various interfaces within the ASSLB.

Main Methods:

• Integration of PPC-SPEs as interlayers with a Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) SSE.
• Systematic analysis of interfacial resistance at the cathode/SSE, Li/SSE, and polymer/LAGP interfaces.
• Fabrication and testing of a LiFePO₄/Li cell utilizing a PPC-LAGP-PPC sandwich structure composite electrolyte (PLSSCE).

Main Results:

• Suppression of Ge⁴⁺ reduction and improved contact between cathode and electrolyte.
• Reduction in Li/SSE interfacial resistance by approximately 35%.
• Significant decrease in cathode/SSE interfacial resistance from 3.2 × 10⁴ to 543 Ω cm².

Conclusions:

• PPC-SPE interlayers effectively mitigate interfacial resistance in ASSLBs.
• The PLSSCE structure enables high-performance ASSLBs with excellent cycling stability.
• This approach offers a viable strategy for advancing ASSLB technology.