Regulating polysulfide conversion and Lithium deposition by hetero-interfacing enable multifunctional separator for...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from poor cycle stability due to the shuttle effect and slow redox kinetics.
• Developing efficient electrocatalysts is crucial to overcome these limitations and enable practical Li-S battery applications.

Purpose of the Study:

• To engineer novel heterostructure electrocatalysts for improved Li-S battery performance.
• To investigate the catalytic mechanism of the designed electrocatalyst on polysulfide intermediates.

Main Methods:

• Fabrication of ultra-thin Nickel hydroxide (Ni(OH)2) nanosheets anchored in a graphene mesh (rGO@Ni(OH)2) using electrostatic self-assembly.
• Electrochemical characterization including capacity retention and cycling stability tests.
• Density functional theory (DFT) calculations to elucidate the catalytic mechanism and interfacial interactions.

Main Results:

• The rGO@Ni(OH)2 integrated separator demonstrated highly conductive network and abundant catalytic sites.
• DFT calculations and kinetic studies revealed optimized adsorption energies for lithium polysulfides (LiPSs) and promoted bidirectional catalytic transformation.
• Achieved uniform lithium deposition with stable cycling for 1000 hours at 0.5 mA cm⁻².
• The Li-S cell exhibited a high initial capacity of 1318 mAh g⁻¹ at 0.1C and sustained 485 mAh g⁻¹ after 100 cycles at 0.2C.

Conclusions:

• The rGO@Ni(OH)2 nano-heterostructure effectively suppresses the shuttle effect and enhances LiPSs conversion kinetics in Li-S batteries.
• This work provides fundamental insights into nano-hetero-interfacial catalysis for advanced battery technologies.
• The developed electrocatalyst shows significant potential for practical, high-performance Li-S batteries.