FLUX SYNTHESIS OF Na 0.44 MnO 2 NANORIBBONS AND THEIR ELECTROCHEMICAL PROPERTIES FOR Na -ION BATTERIES

Well-crystallized Na 0.44 MnO 2 is readily synthesized via a facile NaCl -flux reaction at 850°C for 5 h. The Na 0.44 MnO 2 material exhibits a well-defined nanoribbon structure with dimension of 50–100 nm in thickness and 200–500 nm in width. Electrochemical properties of as-prepared Na 0.44 MnO 2 are thoroughly investigated on assembled nonaqueous Na 0.44 MnO 2 // Na cells using cyclic voltammetry, galvanostatic test, and electrochemical impedance spectroscopy. The results show that the Na 0.44 MnO 2 nanoribbon material can deliver a high capacity of 106 mAh g -1 with stable cycling performance over 40 cycles. In addition, it exhibits a favorable rate capability, delivering a capacity of 90 mAh g -1 at a rate of 1 C. The high capacity retention combined with acceptable rate capability makes the Na 0.44 MnO 2 a promising electrode material for advanced Na -ion batteries.