Polypyrrole-coated sodium manganate hollow microspheres as a superior cathode for sodium ion batteries.

Advanced electrode materials play a very important role in the development of large-scale production of sodium ion batteries. Herein, Na0.7MnO2.05 hollow microspheres with diameters of 2 μm and a shell thickness of 200 nm are prepared and then modified by polypyrrole (PPy) coating. As cathodes for sodium ion batteries, the designed PPy-coated sodium manganate hollow microspheres demonstrate enhanced electrochemical performances with an initial capacity of 165.1 mAh g1, capacity retention of 88.6% at 0.1 A g-1 after 100 cycles and improved rate capability. The excellent electrochemical properties are attributed to the improved electro-conductivity and high stability of hollow spherical structure of sodium manganate oxide particles due to the introduction of conductive polymer coating.