A novel reed‐leaves like aluminum‐doped manganese oxide presetting sodium‐ion constructed by coprecipitation method for high electrochemical performance sodium‐ion battery
Kedi Cai, Xueqin Jing, Yuting Zhang, Lan Li, Xiaoshi Lang
Abstract
Summary In this paper, Al‐doped manganese oxide with presetting sodium‐ion (Na x Mn y Al z O 2 ) is synthesized by a facile coprecipitation method and combines with Na 3 V 2 (PO 4 ) 3 cathode active materials for sodium‐ion battery in order to optimize the electrochemical performances. During the coprecipitation, a stable Na x Mn y Al z O 2 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 Na x Mn y Al z O 2 polynary metal oxides as active material for sodium‐ion capacitor exhibit a very excellent reversibility and low electrochemical ( R ct = 434 Ω) and concentration polarization (D Na+ = 2.2728 × 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 Na x Mn y Al z O 2 polynary metal oxide playing a good depolarization role combined with Na 3 V 2 (PO 4 ) 3 active materials in the mass ratio to 7:3 can bring about the most excellent electrochemical performances.