Surface modification is one of the impressive and widely used technique to improve the electrochemical performance of sodium-ion batteries by modifying the electrode-electrolyte interface. Herein, we used the atomic layer deposition (ALD) to modify the surface of P2-Na0.5Mn0.5Co0.5O2 by sub-monolayer Al2O3 coating on the prefabricated electrodes. Phase purity is confirmed using various structural and morphological studies. The pristine electrode delivered an initial discharge capacity of 154 mAh g(-1) at 0.5C, and inferior rate performance of 23 mAh g(-1) at 40C rate. On the other hand, the interfacial modified cathode with 5 cycles of ALD coating delivers a high capacity of 174 and 45 mAh g(-1) at 0.5C and 40C rate, respectively. The Co-2(+/)3+ redox couple is utilized for the faradaic process with high reversibility along with suppressed P2-O2 phase transition. The presence of the Al2O3 layer acts as an artificial cathode electrolyte interface by suppressing the electrolyte oxidation at higher cutoff potentials. This is clearly validated by the reduced charge transfer resistance of surface modified electrodes after cycling at various current rates. Even at an elevated temperature condition (50 degrees C), interfacial layer significantly improves the safety of the cell and ensures the stability of the cathode. (C) 2020 Elsevier Inc. All rights reserved.