A compressive-strain-engineered TiO₂/rGO heterojunction as a polysulfide mediator.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium-sulfur batteries (LSBs) face challenges like the polysulfide shuttle effect and slow reaction kinetics, limiting their practical use.
• Developing advanced materials for separator modification is crucial for enhancing LSB performance and stability.

Purpose of the Study:

• To engineer a high-performance polysulfide mediator using compressive strain engineering for LSB separator modification.
• To investigate the impact of strained TiO2/reduced graphene oxide (TNGO) heterostructures on polysulfide management and electrochemical performance.

Main Methods:

• Fabrication of a TiO2/reduced graphene oxide (rGO) heterostructure (TNGO) utilizing compressive strain engineering.
• Characterization of the TNGO structure and confirmation of lattice strain in TiO2.
• Modification of polypropylene separators with the TNGO composite and evaluation in LSBs.

Main Results:

• The strained TiO2 lattice in TNGO significantly improved polysulfide chemisorption and accelerated Li+ diffusion.
• TNGO-modified separators effectively mitigated the shuttle effect and enhanced reaction kinetics in LSBs.
• LSBs with TNGO separators exhibited a high initial capacity (1072.7 mAh g-1 at 1C), excellent long-term stability (409.9 mAh g-1 after 1000 cycles), and good performance at high sulfur loading.

Conclusions:

• Compressive strain engineering is a novel and effective strategy for developing advanced polysulfide mediators.
• TNGO-based separator modification offers a promising approach to overcome critical limitations in lithium-sulfur batteries.
• This work paves the way for improved energy storage solutions through tailored material design.