Interfacial Interaction of Multifunctional GQDs Reinforcing Polymer Electrolytes For All-Solid-State Li Battery

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state polymer electrolytes are crucial for next-generation lithium-ion batteries, offering improved safety and energy density.
• A primary limitation of polymer electrolytes is their low ionic conductivity at room temperature.

Purpose of the Study:

• To enhance the ionic conductivity of poly(ethylene oxide) (PEO) based electrolytes.
• To investigate the effect of graphene quantum dots (GQDs) on PEO-based electrolytes for lithium-ion batteries.

Main Methods:

• Incorporation of graphene quantum dots (GQDs) into poly(ethylene oxide) (PEO) polymer matrix.
• Characterization of ionic conductivity, lithium-ion transference number, and mechanical properties of the composite electrolytes.
• Assembly and testing of all-solid-state lithium batteries using the modified electrolytes.

Main Results:

• Graphene quantum dots significantly increased the amorphous regions of PEO, enhancing Li+ mobility and ionic conductivity.
• The hydroxyl and amino groups on GQDs acted as Lewis base sites, promoting lithium salt dissociation and ion pathways.
• Suppression of lithium dendrite formation was observed, attributed to high transference numbers and improved interface stability.
• The GQDs-modified electrolytes enabled batteries with excellent rate performance and cycling stability.

Conclusions:

• Graphene quantum dots are effective dopants for enhancing the performance of solid-state polymer electrolytes.
• The modified electrolytes offer a promising solution for developing safer and higher-energy-density lithium-ion batteries.
• This work demonstrates a viable strategy for overcoming the ionic conductivity limitations in polymer electrolytes.