Intrinsically Safe Gel Polymer Electrolyte Comprising Flame-Retarding Polymer Matrix for Lithium Ion Battery...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Current lithium-ion battery (LIB) electrolytes pose safety risks due to flammability and leakage.
• Polyolefin separators in state-of-the-art (SOTA) LIBs contribute to these safety concerns.

Purpose of the Study:

• To develop a nonflammable gel polymer electrolyte (GPE) for enhanced LIB safety.
• To investigate the performance and safety of phosphonate-based GPEs compared to SOTA GPEs.

Main Methods:

• Chemically bonding a phosphonate moiety to a polymer matrix to create a flame-retardant polymer.
• Fabricating a GPE using the phosphonate-based polymer matrix and a nonaqueous liquid electrolyte.
• Evaluating the flame resistivity, thermal stability, and electrochemical performance of the GPE.

Main Results:

• The phosphonate-based polymer matrix and its GPE exhibited significant flame resistivity.
• The phosphonate-based GPE showed no adverse reactions with lithiated graphite at high temperatures, unlike PVDF-based GPEs.
• LIB cells with phosphonate-based GPE demonstrated good capacity retention and comparable cycle life to SOTA GPEs.

Conclusions:

• Phosphonate-based GPEs offer superior intrinsic safety performance compared to SOTA GPEs.
• The chemical bonding of phosphonate moieties prevents parasitic reactions with electrodes.
• Phosphonate-based polymers represent a promising new class of materials for advanced GPEs in LIBs.