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 g–1, 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 electroconductivity and the high stability of hollow spherical structure of sodium manganate oxide particles due to the introduction of conductive polymer coating.