基于λ-MnO_2的钠离子电容器研究

Study on Sodium Ion Capacitor Based on λ-MnO_2

以商品化锰酸锂（LiMn204）为原料，制备了λ-二氧化锰（λ-MnO2），并作为钠离子电容器的正极材料．采用粉末X线衍射（XRD）对样品进行微观结构分析，采用循环伏安和恒流充放电测试了钠离子电容器的电化学电容性能．结果表明：钠离子电容器在0～2．2V电位区间内的比电容量为49．6F／g；经500次循环后钠离子电容器的比电容为首次的93％，循环性能优良．研究表明，λ-MnO2是钠离子电容器有潜力的电极材料．

λ-MnO2 was prepared with commercial LiMn204 as raw material, and used as the positive electrode in sodium ion capacitor. Phase composition of λ-MnO2 was studied by powder X-ray diffraction （XRD）, and electrochemical capacitive performance of the sodium ion capacitor was tested by cyclic voltammetry and galvanostatic charge/discharge tests. The results show that the specific capacitance of sodium ion capacitor is 49.6 F/g, within potential range of 0-2.2 V;he specific capacitance remains 93% after 500 cycles, showing an excellent cycling stability. It is obvious that λ-MnO2 is a potential electrode material for sodium ion capacitor.