Strain-Induced Magnetic Ordering Unlocks Spin-Conserved Catalysis in Lithium-Oxygen Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Designing advanced ferromagnetic catalysts with intrinsic magnetism and spin polarization is crucial for lithium-oxygen batteries (LOBs).
• Controlling magnetic ordering and spin states at the atomic scale for efficient spin-selective electron transfer remains a challenge.

Purpose of the Study:

• To develop a strain engineering approach for constructing ferromagnetic catalysts.
• To enhance ferromagnetic exchange interactions and spin polarization in cobalt disulfide (CoS2) for improved LOB performance.

Main Methods:

• Lattice tensile strain engineering was applied to cobalt disulfide (CoS2) anchored on reduced graphene oxide (rGO), creating strained s-CoS2/rGO.
• Experimental and theoretical analyses were used to investigate the effects of strain on magnetic properties and catalytic activity.
• The study examined the role of strain-induced lattice distortion in enhancing d-p orbital hybridization and spin-polarized conduction channels.

Main Results:

• A ~4% tensile strain along the (111) plane induced spontaneous parallel alignment of atomic magnetic moments, creating intrinsic magnetic anisotropy and single-domain architectures.
• The strained catalyst (s-CoS2/rGO) exhibited enhanced ferromagnetic exchange interactions and spin polarization.
• This resulted in elevated spin-polarized current densities, a reduced O2 dissociation barrier, and superior catalytic kinetics.

Conclusions:

• The s-CoS2/rGO catalyst demonstrated ultra-long cycling stability exceeding 2000 hours at 200 mA g-1 in LOBs.
• Lattice tensile strain engineering provides a general approach for designing high-performance ferromagnetic catalysts.
• Spin-state engineering is critical for advancing next-generation LOB technologies.