Prelithiation\nMechanism of Silicon Anodes through\nthe Interfacial Destabilization of Lithium Hydride

Prelithiation is\nan effective strategy to compensate for irreversible\ncapacity loss caused by solid–electrolyte interphase (SEI)\nformation during initial cycling of silicon-based anodes. However,\nthe mechanism is complicated due to dynamic phase evolution of metastable\nalloys based on thermodynamic variables. Prelithiation mechanisms\nbetween lithium hydride (LiH) and silicon (Si) anodes were studied.\nLiH can be easily controlled as a reactant due to its slow reactivity.\nThe interfacial destabilization and reaction kinetics of prelithiation\nmechanisms are investigated. Interfacial chemical reactions play a\ncritical role in the prelithiation mechanism, involving the release\nof hydrogen gas. These reactions enable a sacrificial lithium source\nto penetrate the Si structure, leading to formation of Li<sub><i>x</i></sub>Si phases contributing to the prelithiation process\nefficiency. Additionally, Li<sub><i>x</i></sub>Si phase\ncompositions depend on LiH concentrations that are designed to compensate\nfor active lithium loss. An optimized LiH concentration demonstrated\nmore than a 54.9% capacity retention improvement after 100 cycles.\nLi<sub><i>x</i></sub>Si materials can offset the irreversible\ncapacity loss during the first cycle, thereby improving the initially\nlow Coulombic efficiency (ICE), while enhancing the battery cycling\nstability. This research provides insights into interfacial destabilization\nand reaction kinetics of the prelithiation method and significantly\nimproves the electrochemical performance of lithium-ion batteries.