Ionic liquids as potential electrolytes for sodium-ion batteries: an overview

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) are gaining prominence due to sodium's abundance and lower cost compared to lithium.
• Safety concerns with conventional organic solvent-based electrolytes in SIBs necessitate alternative solutions.
• Ionic liquids (ILs) present a promising alternative due to their inherent thermal stability.

Purpose of the Study:

• To provide a comprehensive overview of ionic liquids (ILs) as electrolytes for sodium-ion batteries (SIBs).
• To discuss the properties of ILs relevant to SIB applications, including transport characteristics.
• To highlight strategies for overcoming transport limitations and explore recent applications.

Main Methods:

• Review of existing literature on ionic liquids in sodium-ion battery electrolytes.
• Analysis of the impact of cation, anion, and salt concentration on IL properties.
• Discussion of strategies to improve ionic conductivity and ion transport.
• Examination of recent applications in electrode electrolytes and solid-state electrolytes.

Main Results:

• Ionic liquids exhibit superior thermal stability over organic solvents, addressing key safety concerns in SIBs.
• Neat ILs and IL-based mixtures show potential as electrolytes for both negative and positive electrodes.
• Transport properties of ILs are influenced by cation/anion choice and salt concentration, often requiring optimization.
• Strategies to enhance transport properties are crucial for realizing the full potential of ILs in SIBs.

Conclusions:

• Ionic liquids are a viable and safer alternative electrolyte for sodium-ion batteries.
• Further research into optimizing IL transport properties is essential for competitive SIB performance.
• ILs, particularly in mixtures and solid-state formulations, hold significant promise for next-generation energy storage devices.