Single crystalline Na0.44MnO2 nanorods of the orthorhombic tunnel structure have been prepared via reverse microemulsion method. As a cathode material, the Na0.44MnO2 electrode exhibits a reversible capacity of 85.14 mAh g(-1) at the current density of 100 mA g(-1) with 94.4% capacity retention for 50 cycles. It also demonstrates good high-rate performance, delivering approximately 63.1% of the initial capacity at a current density of 1000 mA g(-1). The outstanding results prove that Na0.44MnO2 is a promising cathode material for sodium-ion batteries. (C) 2015 The Electrochemical Society. All rights reserved.