Synergistic Prelithiation and In Situ Nitrogen Doping via LiN in SiO Anodes: A Dual-Benefit Pathway to Achieving Enhanced Li Kinetics and High Initial Coulombic Efficiency.

Silicon monoxide (SiO) has garnered significant attention as a promising anode material for high-energy-density lithium-ion batteries due to its lower volume expansion relative to pure silicon (Si) and its higher capacity compared to graphite. Nevertheless, the poor intrinsic electronic/ionic conductivity and the low initial Coulombic efficiency (ICE) of SiO result in inferior rate capability and inadequate practical energy density, hindering its commercial viability. Here, a simultaneous prelithiation and in situ nitrogen (N) doping approach for SiO utilizing lithium nitride (LiN), which significantly enhances both the ICE and lithium-ion (Li) diffusion kinetics, is proposed. N atoms are not only incorporated into the carbon layer on the surface of SiO but also form a uniformly distributed amorphous LiSiN phase within the SiO, facilitating Li transport. Molecular dynamics simulations demonstrate that the Li diffusion coefficient of amorphous LiSiN is significantly higher than that of other crystalline phases present in the prelithiated SiO matrix. The 1.5 Ah pouch cells further validate that the SiON-0.175/graphite||NCM811 exhibits a high ICE of 88.06%, and it retains 51.5% of its capacity even under 4C fast charging conditions. This study offers new insights into the development of next-generation SiO anode materials with high ICE and high-rate performance.