Interlayer complementary design of X3N/NbSe2 (X  <b>=</b>  C, Si) heterostructures for high-performance lithium-ion battery anodes: A first-principles study

Monolayer transition metal dichalcogenides and nitrides often suffer from inherent limitations as LIB anode materials, such as the poor Li adsorption of C3N, the sluggish Li mobility of Si3N, and the low capacity of NbSe2. To overcome these individual drawbacks, we construct X3N/NbSe2 (X = C, Si) heterostructures and systematically evaluate their potential via first-principles calculations. Both are thermodynamically stable and exhibit markedly enhanced stiffness. Notably, C3N/NbSe2 achieves a Young's modulus of 413.51–430.63 N m−1, significantly outperforming its monolayer counterparts and most reported 2D materials. The introduction of NbSe2 dramatically enhances the Li adsorption strength of C3N and the Li mobility of Si3N. Specifically, the adsorption energy of C3N/NbSe2 is enhanced by 0.29–2.94 eV compared to that of pristine C3N, while the migration energy barrier of Si3N/NbSe2 is reduced by 0.15–0.20 eV relative to that of Si3N. Additionally, C3N/NbSe2 delivers a high theoretical capacity of 521.92 mAh g−1—far exceeding that of pristine NbSe2—with a reasonable average open-circuit voltage of 0.26 V. Both heterostructures retain metallic character after Li adsorption, guaranteeing high electronic conductivity, and exhibit good wettability with common electrolytes, facilitating charge transfer. Overall, the complementary advantages within these heterostructures effectively mitigate the weaknesses of their constituents. With its balanced combination of high stiffness, large theoretical lithium capacity, and low migration barrier, C3N/NbSe2 emerges as a particularly promising anode material for high-performance LIBs.