二氧化锰纳米片的高原子效率制备及其电容器性能

Highly atom-efficiency synthesis of MnO_2 nanosheets for supercapacitors

Hummers法是较为常用的制备氧化石墨的一种方法,然而在此过程中会产生含有大量Mn2+的废液。对废液中Mn2+的浓度进行调控,然后加碱液沉淀,分别得到了四氧化三锰纳米颗粒和二氧化锰纳米片。将具有较大比表面的二氧化锰纳米片作为电极材料,测试了其电化学性能。结果显示,当电流密度为0.1 A/g时,二氧化锰纳米片比容量可达315.0 F/g。在1 A/g下循环1 000次,其比容量保持率为93.3%。此种方法不仅大大降低了废液排放的危害,而且高原子效率制备了高性能的超级电容器电极材料。

A large amount of wastewater containing a large amount of Mn ion is produced by Hummer＇ s method, which is one of most frequently used methods to prepare graphite oxide.Mn304 nanoparticles and MnO2 nanosheets were synthesized respectively by a facile treatment of the wastewater containing Mn2＋ by KOH solution.The electrochemical performance of MnO2 nanosheets as the electrode materials was tested.Results showed that the specific capacitance of MnO2 nanosheets electrode could reach 315.0 F/g at 0.1 A/g.And the specific capacitance retention at a current density of 1 A/g for MnO2 nanosheets could retain 93.3% of the initial capacitance after 1 000 cycles.Obviously, a highly atom-efficiency strategy was showed for preparation of supercapacitor electrode materials with high performance by a facile treatment of the wastewater and the harm of waste liquid discharge was greatly reduced at the same time.