Current‐Adaptive Li‐Ion Storage Mechanism in High‐Rate Conversion‐Alloying Metal Chalcogenides.

Beyond the high theoretical capacity, conversion‐alloying metal chalcogenides (CAMCs) exhibit exceptional high‐rate performance as Li‐ion battery electrodes. However, the inherent origin of the high‐rate performance remains elusive, especially given the lower intrinsic conductivity of CAMCs. Here, the correlation between phase evolution and charge transport dynamics in fully activated CAMCs is systematically investigated, elucidating a current‐adaptive Li‐ion storage mechanism to explain the anomalous high‐rate performance. Briefly, the deconversion reaction manipulated by ion diffusion acts as a "regulator" to adaptively modulate the transition from metal (high electronic conductivity) and lithium chalcogenides (high ionic conductivity) to CAMCs, thus removing the charge transport bottleneck without affecting the formation of the metal feedstock required for the alloying reaction. On this basis, the high capacity can be maintained at high rates through a "fading‐free" alloying reaction. This study offers a novel perspective for the design of high‐rate electrode materials. [ABSTRACT FROM AUTHOR]