Superior Cycling Stability in Zinc‐Ion Batteries with Ca ²⁺ ‐Induced Cathode‐Electrolyte Interface and Phytic Acid: Experimental Validation of Theoretical Predictions

Abstract This study investigates the impact of Ca ²⁺ and phytic acid (PA) pre‐insertion on the performance of vanadium oxide (V ₆ O ₁₃ ) as a cathode material for aqueous zinc‐ion batteries. Ab initio molecular dynamics (AIMD) simulations reveal that the diffusion coefficient of Ca ² ⁺ is higher than that of Zn ²⁺ , leading to the preferential extraction of Ca ² ⁺. The extracted Ca ² ⁺ readily forms a dense cathode‐electrolyte interphase (CEI) with SO₄ ^{2 −} on the electrode surface, effectively mitigating electrode dissolution. Furthermore, density functional theory (DFT) calculations indicate that the incorporation of Ca ² ⁺ lowers the diffusion energy barrier for Zn ² ⁺, facilitating its diffusion. Additionally, PA insertion stabilizes the interlayer spacing of V ₆ O ₁₃ , and its strong chelating ability stabilizes the structure by preventing collapse during cycling. Experimental validation through a one‐step solvothermal method confirms these theoretical predictions. The CaVO‐PA composite exhibits excellent cycling stability, with a capacity retention rate increasing from 60% to 102% after 3000 cycles at 10 A g ⁻ ¹. Even at 20 A g ⁻ ¹, it delivers a specific capacity of 170.2 mAh g ⁻ ¹ with stable Coulombic efficiency. After 10 000 cycles, the capacity shows no significant degradation, demonstrating superior cycling stability and high current tolerance, thereby confirming the effectiveness of the CEI and PA in enhancing electrochemical performance.