纳米MnO_2的制备及显微结构和电化学性能

Preparation,Microstructure and Electrochemical Performance of Nano-Sized MnO_2

将KMnO4负载在介孔二氧化硅KIT-6模板上,在不同温度(400~700℃)煅烧制备纳米MnO_2,研究了不同煅烧温度下纳米MnO_2的显微结构和电化学性能。结果表明:当煅烧温度为400℃时,制备得到的纳米MnO_2只由具有层状结构的δ-MnO_2组成,当煅烧温度升高至500℃时,纳米MnO_2由具有层状结构的δ-MnO_2和少量具有隧道结构的α-MnO_2组成,当煅烧温度为600,700℃时,纳米MnO_2均由具有隧道结构的α-MnO_2组成,且α-MnO_2分别呈有序介孔形貌和棒状形貌;具有隧道结构的α-MnO_2的循环稳定性优于具有层状结构δ-MnO_2的,在100mA·g-1电流密度下经50次循环充放电后仍具有100mAh·g^(-1)以上的放电容量。

Nano-sized MnO2 was synthesized by loading KMnO4 on a mesoporous silica KIT-6 template and calcination at different temperatures（400-700 ℃）.The microstructure and electrochemical performance of nanosized MnO2 at different calination temperatures were studied.The results show that the prepared nano-sized MnO2 was composed ofδ-MnO2 with layered structure when calcined at 400 ℃,δ-MnO2 with layered structure and a small amount ofα-MnO2 with tunnel structure when calcined at 500 ℃,α-MnO2 with tunnel structure which presented ordered mesoporous morphology and rod shape morphology,respectively,when calcined at 600 ℃ and700 ℃.Theα-MnO2 with tunnel structure showed a better cycling stability than that ofδ-MnO2 with layered structure,and had a discharge capacity more than 100 mAh·g^-1 after 50 cycles of charge-discharge at a current density of 100 mA·g-1.