A novel reed-leaves like aluminum-doped manganese oxide presetting sodium-ion constructed by coprecipitation method for high electrochemical performance sodium-ion battery

In this paper, Al-doped manganese oxide with presetting sodium-ion (NaxMnyAlzO2) is synthesized by a facile coprecipitation method and combines with Na3V2(PO4)(3) cathode active materials for sodium-ion battery in order to optimize the electrochemical performances. During the coprecipitation, a stable NaxMnyAlzO2 polynary metal oxide with Mn and Al molar ratio to 3:1 shows a special micromorphology similar to that of reed leaves, which makes it have a more ideal electrochemical specific surface area and ample mass transfer channels for rapid sodium-ion insertion and desorption. Electrochemical test indicates that reed-leaves like NaxMnyAlzO2 polynary metal oxides as active material for sodium-ion capacitor exhibit a very excellent reversibility and low electrochemical (R-ct = 434 omega) and concentration polarization (DNa+ = 2.2728 x 10(-11) cm(2) s(-1)). Specific discharge capacity can achieve to 73.76 F g(-1) at 100 mA g(-1) current density corresponding to 368.8 m(2) g(-1) electrochemical specific surface area. After 200 cycles, the capacity retention rate can be maintained at 81.81%. In addition, reed-leaves like NaxMnyAlzO2 polynary metal oxide playing a good depolarization role combined with Na3V2(PO4)(3) active materials in the mass ratio to 7:3 can bring about the most excellent electrochemical performances.