| Compared with Li ion battery,magnesium ion battery has attracted much attention due to its relatively large capacity and safety for application.MgMn2O4,as an important cathode material,shows high open circuit voltage（2.8 V）and large theoretical specific capacity(270 m Ahg-1),and has great advantages in thermodynamics and dynamics.In this paper,MgMn2O4 and Fe-doped MgMn2O4 were synthesized by sol-gel method and hydrothermal method,respectively.The effects of calcining temperature and dwelling time on the phase evolution,microstructures and surface morphology of the products were investigated.The electrochemical properties of the products were also studied.The results showed that the major phase of MgMn2O4 with tetragonal structure was obtained by sintering precursor at 550-750℃for 5-12 h,in which the precursor was prepared by sol-gel method.In addition,a very small amount of MgMn2O4 was observed in the products.A three-electrode cell system was used to evaluate the electrochemical properties.The working electrode was prepared by loading the products as active substance on Ti substrate.A platinum sheet and an Ag/AgCl electrode were used as the counter electrodes and the reference electrodes,respectively.Charge and discharge measurements were carried out at 0.01 C.The results show that MgMn2O4 samples synthesized by sol-gel method exhibits the discharge specific capacity of 54.0 mAhg-1without existing charge and discharge platform.And its specific capacity is stable at 30.0 mAhg-1after 15 circulation weeks.The single phase of MgMn2O4 with hollow porous microstructures can be obtained by hydrothermal method.The discharge specific capacity is 53.5 mAhg-1after 50 cycles at 0.01C.A cubic MgFe0.5Mn1.5O4 phase has been synthesized in Fe-doped system using sol-gel method.Like undoped system,no obvious charge/discharge platform is observed.And the maxium capacity was 50.0 m Ahg-11 and remained at 30 m Ahg-11 after 49 cycles. |
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