Prepare and optimize NASICON-type Na4MnAl(PO4)3 as low cost cathode for sodium ion batteries

Though the Na 4 MnAl(PO 4 ) 3 (NMAP) show the lower cost, higher energy density and environmental friendless than Na 3 V 2 (PO 4 ) 3 , the NMAP exhibits the low capacity and undesirable cycling stability. Herein, the Na 4 MnAl(PO 4 ) 3 was synthesized by a simple sol-gel method. First, the impacts of various synthesized temperature and calcined time on electrochemical property of NMAP were systemically revealed. It is impressive that the optimized NMAP among synthesized samples exhibits the obviously improved specific capacity and cycling stability. The NMAP can deliver the specific capacity of 110 mAh g −1 at 0.1 C and maintain the capacity retention of 50% after 100 cycles. The electrochemical impedance spectroscopy and various scanning CV tests are applied to clarify the dynamics of Na + diffusion electrochemical reaction . Moreover, the reason for capacity decay is revealed by the XRD and electrochemical measurements. This investigation can provide meaningful reference for the developed low cost NMAP and optimized its electrochemical property.