Influence of Iron Sulfide Nanoparticle Sizes in Solid-State Batteries*

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Intercalation-based lithium-ion batteries face performance limitations.
• Solid-state conversion batteries offer a promising alternative for future energy storage.
• Iron disulfide (FeS2) is an abundant material with high theoretical specific capacity, making it attractive for battery cathodes.

Purpose of the Study:

• To synthesize iron disulfide (FeS2) nanoparticles with controlled sizes.
• To evaluate the electrochemical performance of FeS2 nanoparticles in solid-state cells.
• To investigate the effect of particle size on the performance of FeS2 conversion electrodes.

Main Methods:

• Solvothermal synthesis was employed to prepare FeS2 nanoparticles.
• Particle size was controlled, yielding samples between 10 nm and 35 nm in diameter.
• Electrochemical performance was assessed using solid-state cells with a Li-argyrodite solid electrolyte.

Main Results:

• FeS2 exhibited irreversible reduction during the initial discharge, followed by stable cycling of reduced species.
• Smaller FeS2 nanoparticle dimensions positively impacted material utilization.
• Improved performance in smaller particles is attributed to increased interfacial contact area and reduced ion diffusion pathways.

Conclusions:

• Morphological design, specifically particle size reduction, is crucial for optimizing the performance of FeS2 conversion electrodes.
• These findings underscore the potential of FeS2 in solid-state batteries by enhancing its practical capacity.
• The study highlights the general importance of controlling morphology for advanced conversion electrode materials in solid-state energy storage.