Lithium-Ion Dynamic Interface Engineering of Nano-Charged Composite Polymer Electrolytes for Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Composite polymer electrolytes (CPEs) are crucial for solid-state lithium-metal batteries (ASSLMBs).
• Conventional nanofillers struggle to achieve simultaneous robust electrochemical and mechanical interfaces in CPEs.
• Surface properties of nanofillers critically influence CPE performance.

Purpose of the Study:

• To engineer lithium-ion dynamic interfaces (Li+-DI) in nano-charged CPEs (NCCPEs) by regulating halloysite nanotube (HNT) surface charges.
• To investigate the impact of HNT surface charge characteristics on the mechanical and ion-conduction behaviors of NCCPEs.
• To enhance the electrochemical and mechanical stability of ASSLMBs.

Main Methods:

• Surface charge modification of halloysite nanotubes (HNTs).
• Fabrication of nano-charged composite polymer electrolytes (NCCPEs) using modified HNTs.
• Characterization of Li+-DI, mechanical properties (toughness), ion conductivity, and electrochemical performance of NCCPEs.
• Assembly and testing of Li|NCCPE|LiFePO4 batteries.

Main Results:

• Positively charged HNTs (HNTs+) significantly altered Li+-DI, leading to a higher Li+ transference number (0.86) compared to negatively charged HNTs (HNTs-, 0.73).
• HNTs+ improved NCCPE toughness by 2000% due to strong Li+-mediated interface compatibilization.
• HNTs+ effectively weakened Li+ solvation and promoted a LiF-rich solid-electrolyte interphase, enhancing battery cycle life (144.9 mAh g-1 after 400 cycles at 0.5 C, 78.6% retention).

Conclusions:

• Regulating nanofiller surface charges is a viable strategy for engineering dynamic interfaces in CPEs.
• Positively charged HNTs offer superior performance in NCCPEs for ASSLMBs by optimizing mechanical and electrochemical properties.
• This work provides fundamental insights into nanofiller surface charge effects on interfaces within solid-state batteries.