低温固相法制备的纳米α-MnO_2的性能

Performance of nano-α-MnO_2 synthesized via low temperature solid-phase method

以KMnO4和MnCl2·4H2O为原料,采用低温固相法制备锌离子电池正极材料α-MnO2,通过XRD、透射电子显微镜（TEM）和电池测试,研究KMnO4与MnCl2·4H2O物质的量比对材料结构及电池性能的影响。所得材料为直径7-10 nm、长度50-120 nm的纳米级棒状α-MnO2。KMnO4与MnCl2·4H2O物质的量比为2∶3时,制备的锌离子电池以100 mA/g的电流在1.0-2.0V循环,比容量最高为143 mAh/g,第50次循环的容量保持率为76.8%,库仑效率保持在90%以上。随着KMn O4与MnCl2·4H2O物质的量比的提高,材料的结晶性提高,纳米棒的直径和长径比减小,有利于提高电池的比容量。

Zinc ion battery cathode material α-MnO2 was prepared via low-temperature solid-phase method using KMnO4 and MnCl2·4H2O as raw materials. XRD ,transmission electron microscope （TEM）and battery tests were used to study the influence of the mole ratio of KMnO4 and MnCl2·4H2O to the structure and performance. The obtained material was stick-like nano α-MnO2 ,the diameter was about 7 - 10 nm,the length was about 50 - 120 nm. When the mole ratio of KMnO4 and MnCl2·4H2O was 2： 3,the prepared cell had the maximum specific capacity of 143 mAh/g when cycled with the current of 100 mA/g in 1.0 - 2. 0 V,the capacity retention rate was 76. 8% after 50 cycles, the Coulombic efficiency retained above 90%. As the mole ratio of KMnO4 and MnCl2·4H2O increased,the crystallization property of the material improved, the diameter and aspect ratio decreased, these would increase the specific capacity of the cell.