采用溶胶-凝胶法制备得到了主相为四方结构的MgMn2O4。研究了煅烧温度对产物的相演化和表面形貌的影响，比较了电化学循环稳定性。结果表明，550℃烧结得到了表面呈现多孔通道和孔洞的MgMn2O4 (MMO550)，在40 mA/g电流密度下，最大放电比容量为54.0 mAh/g; 与碳纳米管于400℃复合2 h后，CNT形成的导电网格有效地将MgMn2O4颗粒连接起来，得到MMO/CNT样品的首次放电比容量可达118.0 mAh/g，是未复合MMO550最大放电比容量的2.2倍，循环30周后容量保持在88.1 mAh/g。

Rechargeable magnesium ion batteries (MIB) as next-generation secondary battery systems have attracted increasing attention due to the high theoretical volumetric capacities, low cost and safety of Mg metal anodes. One of the key challenges in MIB is to develop cathode materials with higher specific capacity. Tetragonal spinel structure MgMn2O4 can be as MIB cathode material in aqueous electrolyte environments. However,the strong polarization and low kinetics diffusion of Mg2+ ion results a sluggish Mg migration in MgMn2O4. Herein, nanostructured MgMn2O4 samples were prepared via a simple sol-gel route followed by annealing using magnesium nitrate, manganese nitrate and critic acid as raw materials. The crystal structures and the morphologies of the products were analyzed by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Electrochemical measurements of the products were carried out in a three-electrode breaker cell. The results showed that the samples annealed at 550℃ (MMO550) exhibited the maximum discharge specific capacity of 54.0 mAh/g at a current density of 40 mA/g, which was almost twice that of 750℃ samples (MMO750). The average grain size of MMO550 was about 30 nm analyzed by XRD and TEM, respectively. The MMO550 samples comprise microaggregated with channels and pores on the surface observed by FESEM, which were favorable for the effective contact between the electrolyte and particles. Further, nanocomposites of MgMn2O4 and carbon nanotube (MMO/CNT) obtained by annealing MMO550 with adding 5wt% CNT at a temperature of 400℃ for 2 h, exhibited the first discharge specific capacity of 118.0 mAh/g and capacity retention of 75% after 30 cycles. The Coulombic efficiency of MMO/CNT was very stable and above 95%. This outcome could be attributed to the improvement of conductivity provided by CNTs. FESEM and TEM results confirmed that CNTs can be acted as conductive grid connecting the MgMn2O4 particles effectively.