First-principles computational design of a novel two-dimensional SHfSiN₂ anode for lithium, sodium, and multivalent metal ion batteries

Advances in electrochemical energy systems for power applications increasingly rely on first-principles computational materials design to identify electrode materials with superior properties beyond the limits of conventional materials. In particular, two-dimensional anode materials show great promise for next-generation battery applications due to their unique properties. This work employs first-principles calculations to design and investigate a SHfSiN₂ monolayer and assess its potential as an efficient anode material for lithium, sodium, and multivalent metal-ion batteries. The pristine SHfSiN₂ monolayer demonstrates excellent thermodynamic and dynamic stability, intrinsic polarization, and semiconducting behavior with an indirect band gap of 0.50 eV. As an anode material for Li-ion batteries, it exhibits a high theoretical specific capacity of 521 mAh g−1, a favorable open-circuit voltage of 0.421 V, and ultralow Li-ion diffusion barriers ranging from 0.02 to 0.08 eV, indicating fast ion transport kinetics and outstanding rate performance. The SHfSiN₂ monolayer also exhibits excellent electrochemical performance for Na+, Mg2+, and Ca2+ storage, with high theoretical capacities of 397.4, 389.7, and 317.0 mAh g−1, respectively. Favorable open-circuit voltages, pronounced charge transfer, and low diffusion barriers indicate stable adsorption and fast ion migration, highlighting SHfSiN₂ as a versatile anode material for next-generation metal-ion batteries.