Aqueous sodium-ion batteries (ASIBs) hold promise for large-scale energy storage but suffer from limited energy density and lifespan due to water decomposition. This study presents an alkaline-type ASIB with a Mn-based Prussian blue analogue cathode, achieving 13,000 cycles at 10 C and 88.9 Wh kg⁻¹ energy density at 0.5 C. A nickel/carbon layer suppresses oxygen evolution and enhances battery durability by creating a H₃O⁺-rich environment near the cathode and in-situ embedding Ni atoms into the cathode.
