B-Nb-C Bond-Mediated Heterogeneous Interface Passivation for Enhanced Li-S Battery Performance

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Niobium boride (NbB2) exhibits promising catalysis for lithium-sulfur batteries but suffers from catalyst poisoning due to strong sulfur affinity.
• Existing heterogeneous coatings have weak interfacial contact and high resistance, limiting their effectiveness.

Purpose of the Study:

• To develop a novel interface engineering strategy for NbB2-based electrocatalysts to overcome poisoning in lithium-sulfur batteries.
• To create a poison-resistant catalyst with enhanced interfacial properties for improved battery performance.

Main Methods:

• Fabrication of NbB2@boron-doped carbon (NbB2@BC) core-shell nanowires.
• Utilizing DFT theoretical calculations and experimental validation to investigate interfacial properties.
• Separator modification with the developed NbB2@BC material.

Main Results:

• A spontaneous built-in electric field (BIEF) and B-Nb-C chemical bonds were formed at the NbB2@BC interface.
• The interface engineering strategy weakened NbB2's sulfur adsorption and accelerated polysulfide conversion and electron transfer.
• The modified separator (NbB2@BC/PP) achieved a high capacity (912.7 mAh g-1) and excellent cycling stability (87% retention) under demanding conditions.

Conclusions:

• The B-Nb-C bond-mediated interface passivation effectively prevents catalyst poisoning in lithium-sulfur batteries.
• This innovative strategy offers a pathway for developing robust and high-performance electrocatalysts for advanced energy storage devices.