For the development of sodium ion secondary batteries, performance improvement in the positive electrode is the main area of research in recent times. Enhancement in electrochemical performance of Na0.44MnO2(NMO) material as a positive electrode material for sodium ion secondary batteries plays a vital role. In this work, the NMO orthorhombic compound was prepared through sol–gel auto combustion process and characterized. Its electrochemical properties are investigated and discussed. The material displays a discharge capacity of about 102.5 mAh/g at a low current rate (C/20), which decreases to 36.75 mAh/g at a relatively higher rate (2C). The capacity retention at C/10 after 50 cycles is 85.7%. The evaluation of Na-ion diffusion coefficients (DNa+) in NMO is accomplished by potentiostatic intermittent titration technique (PITT) test and galvanostatic intermittent titration technique (GITT) test. The obtained values for the Na-ion diffusivity are ranging between 10−14 and 10−15 cm2 s−1.