Carbon-Mediated Chemical Prelithiation: A Mild and Scalable Strategy for High-Performance Silicon-Hard Carbon Composite Anodes

초록

While silicon-based anodes offer high theoretical capacity, their commercial adoption is hindered by significant irreversible lithium loss during the initial cycle. Traditional chemical prelithiation using highly reducing lithium-arene complexes often suffers from poor stability and harsh reaction conditions. In this work, we present a novel, industrially compatible prelithiation strategy using a biphenyl-tetrahydrofuran (BP-THF) complex. Unlike conventional reagents, BP?THF possesses a mild redox potential that avoids direct, aggressive silicon lithiation. Instead, we utilize the hard carbon (HC) framework as a mediator; lithium is strategically incorporated into the HC defect sites, which then effectively compensates for the initial capacity loss of the composite. Furthermore, this process facilitates the formation of a robust, inorganic-dominant solid-electrolyte interphase (SEI), significantly enhancing interfacial stability. We demonstrate that the efficiency of this carbon-mediated process can be finely tuned by optimizing the HC microstructure through controlled heat treatment. This work offers a chemically stable and energy-efficient pathway for activating next-generation silicon-based anodes, bridging the gap between laboratory research and large-scale industrial applications.