Sodium-rich manganese oxide porous microcubes with polypyrrole coating as a superior cathode for sodium ion full batteries

Polypyrrole-coated high Na content Na0.91MnO2 porous microcubes are prepared through high temperature calcination followed by a chemical ice water bath process. The higher sodium content of Na0.91MnO2 makes capacity increase up to 50 mAh g−1 compared with Na0.7MnO2.05. The thus wider interlayer space makes ion/electron insertion/extraction faster. Porous structure providing shorter ion/electron diffusion distance compared with hollow sphere structure. The conductive polymer modified sodium manganate oxide cathode for sodium ion full batteries exhibits ultrahigh initial capacity, cycling stability and rate capability. [Display omitted] Highly conductive cathode material with enhanced Na+ diffusion kinetics is of great importance in the exploration of sodium ion batteries. In this work, Na0.91MnO2 porous microcube which is coated with highly conductive polypyrrole (PPy) is obtained. The high Na content in the layered sodium manganate oxide brings about wider interlayer distance resulting in high capacity and electrochemical kinetics. The higher sodium content of Na0.91MO2 makes capacity increase up to 50 mAh g−1 compared with Na0.7MnO2.05. Furthermore, the well-designed combination between porous structure and conductive PPy coating exhibits fast ion/electron transfer inside the electrode and high cycling stability. The PPy coated Na0.91MnO2 delivers a high initial capacity of 208 mAh g−1, encouraging capacity retention and rate capability. Based on the porous Na0.91MnO2@PPy cathode, the sodium ion full cells with puffed millet porous carbon anode show remarkably stable cycling and high-rate performances.