<p>By employing the frst-principle calculations, the voltage plateau, structure evolution, and charge compensation mechanism during the desodiation process are discussed. Our results reveal that α-Na₂FePO₄F exhibits small volume changes (only 5.5%) through the charge/discharge cycle, indicating excellent structural stability. Theoretical capacity of α-Na₂FePO₄F reaches 248 mAh/g, with four voltage plateaus during the desodiation process. The first two voltage plateaus involve charge compensation through the oxidation of Fe²⁺ to Fe³⁺. The third and fourth platforms involve charge compensation by oxygen ions. The magnetic moments and density of states analysis reveal that the oxidation of Fe³⁺ to Fe⁴⁺ does not happen during the whole desodiation process, as the energy level of Fe⁴⁺ lies far below the Fermi level (more than 6&#xa0;eV). Moreover, the Na⁺ diffusion coefficient in α-Na₂FePO₄F is higher than that in β-Na₂FePO₄F, consistent with the previous study. This work provides insights for evaluating α-Na₂FePO₄F as a candidate cathode material for sodium-ion batteries.</p>