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

Conversion-type transition metal-based materials (MZ_<i>x</i>) are considered promising cathodes for lithium metal batteries due to their low cost, abundant availability, and high theoretical energy density. However, they suffer from rapid capacity decay caused by the transformation into two inhomogeneous phases during discharge. Herein, we use a pulse current discharge activation method (under 3C) to induce homogeneous phase nucleations. As a result, the microsized FeS₂ cathode transforms into a homogeneous mixture of nanosized Fe and Li₂S, effectively mitigating volume expansion. It exhibits exceptional cycling performance, delivering a specific capacity of 572.8 mAh g^-1 after 800 cycles at 0.33C. Even at a high areal capacity of 5.4 mAh cm^-2, it undergoes 180 cycles with a capacity retention of 89.3% at 0.33C. This work highlights the crucial role of homogeneous nucleation in achieving long cycling life for conversion-type cathodes.