Single lithium-ion conducting solid polymer electrolytes: advances and perspectives

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Classical lithium-ion batteries (LIBs) face limitations in safety and energy density due to unstable liquid electrolytes.
• Rechargeable lithium metal batteries (LMBs) offer higher theoretical capacity but are hindered by dendritic lithium growth and capacity fading in liquid electrolytes.
• Solid polymer electrolytes (SPEs) present a safer alternative, but traditional dual-ion conductors suffer from concentration polarization.

Purpose of the Study:

• To review synthetic strategies for single lithium-ion conducting solid polymer electrolytes (SLIC-SPEs).
• To discuss the fundamental physical and electrochemical properties of various SLIC-SPEs.
• To highlight SLIC-SPEs with high ionic conductivity and high lithium-ion transference numbers (LTN) for advanced LMBs.

Main Methods:

• Review of existing literature on SLIC-SPEs synthesis and characterization.
• Analysis of different types of SLIC-SPEs, including organic polymers, hybrid polymers, and anion acceptors.
• Discussion of physical and electrochemical properties, focusing on ionic conductivity and LTN.

Main Results:

• SLIC-SPEs, where anions are immobilized, overcome the limitations of dual-ion conducting SPEs.
• Benefits of SLIC-SPEs include a high lithium-ion transference number (LTN), suppressed anion polarization, and reduced lithium dendrite growth.
• Various SLIC-SPEs based on different polymer architectures and anion immobilization strategies have been reported.

Conclusions:

• SLIC-SPEs are crucial for enhancing the safety and performance of next-generation rechargeable lithium metal batteries.
• Further research should focus on optimizing SLIC-SPEs for high ionic conductivity and stability.
• Addressing current challenges in SLIC-SPE development will pave the way for practical LMB applications.