Pulse Current-Induced Homogeneous Phase Nucleation for High-Performance Conversion-Type Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Conversion-type transition metal sulfides (e.g., FeS2) are promising for lithium metal batteries due to high energy density and low cost.
• These materials suffer from capacity fade due to inhomogeneous phase transformations during cycling.

Purpose of the Study:

• To develop a method for stabilizing conversion-type cathodes.
• To enhance the cycling performance and energy density of iron disulfide (FeS2) cathodes in lithium metal batteries.

Main Methods:

• Utilized a pulse current discharge activation method (at 3C) to promote homogeneous phase nucleation.
• Investigated the structural transformation of microsized FeS2 into nanosized Fe and Li2S.

Main Results:

• The pulse current method successfully induced homogeneous nucleation, forming a nanosized Fe and Li2S mixture.
• Achieved a specific capacity of 572.8 mAh g⁻¹ after 800 cycles at 0.33C.
• Demonstrated high capacity retention (89.3% over 180 cycles) at an areal capacity of 5.4 mAh cm⁻².

Conclusions:

• Homogeneous nucleation is critical for mitigating volume expansion and improving the longevity of conversion-type cathodes.
• The pulse current discharge activation method offers a viable strategy for enhancing lithium metal battery performance.