Experimental and Computational Insights into Built-In Electric Field at Bronze TiO₂-Expanded Graphite Interface for...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Interfacial engineering is key to improving ion transport and electron mobility in lithium-ion batteries (LIBs).
• Built-in electric fields (BIEFs) at interfaces can accelerate Li+ diffusion, but experimental validation in intercalation materials is lacking.

Purpose of the Study:

• To experimentally validate the concept of BIEF induction for enhanced ion transport in intercalation-type materials.
• To investigate the performance of bronze titanium oxide (TiO2(B)) integrated with expanded graphite (EG) as a high-performance LIB anode.

Main Methods:

• Fabrication of TiO2(B)/EG composite material.
• Kelvin probe force microscopy (KPFM) to confirm BIEF.
• Electrochemical testing including galvanostatic intermittent titration (GITT) and electrochemical impedance spectroscopy (EIS).
• Density functional theory (DFT) calculations.

Main Results:

• A strong interfacial BIEF was generated in the TiO2(B)/EG composite, confirmed by KPFM and DFT.
• The TiO2(B)/EG electrode exhibited a specific capacity of 75 mAh g-1 at 10 A g-1.
• Excellent cycling stability with 70% capacity retention after 1000 cycles at 2 A g-1.
• Reduced charge-transfer resistance and enhanced Li+ diffusion were observed.

Conclusions:

• BIEF modulation is an effective strategy to overcome kinetic limitations in intercalation anodes.
• The TiO2(B)/EG composite demonstrates potential for next-generation high-power, fast-charging LIBs.
• This study provides experimental evidence for BIEF's role in enhancing battery performance.