Superior Cycling Stability in Zinc‐Ion Batteries with Ca2+‐Induced Cathode‐Electrolyte Interface and Phytic Acid: Experimental Validation of Theoretical Predictions

This study investigates the impact of Ca2+ and phytic acid (PA) pre-insertion on the performance of vanadium oxide (V6O13) as a cathode material for aqueous zinc-ion batteries. Ab initio molecular dynamics (AIMD) simulations reveal that the diffusion coefficient of Ca2⁺ is higher than that of Zn2+, leading to the preferential extraction of Ca2⁺. The extracted Ca2⁺ readily forms a dense cathode-electrolyte interphase (CEI) with SO₄2 - on the electrode surface, effectively mitigating electrode dissolution. Furthermore, density functional theory (DFT) calculations indicate that the incorporation of Ca2⁺ lowers the diffusion energy barrier for Zn2⁺, facilitating its diffusion. Additionally, PA insertion stabilizes the interlayer spacing of V6O13, 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.