Study Of MnO₂/Bamboo-Based Activated Carbon Composites As Electrode Materials For Supercapacitor

Materials are fast developing with the improvement of human's living standard. Original biomaterials get more and more attention since traditional petrochemical energy is deficient, and novel materials cannot meet the demands. As an original biomaterial, bamboo has extensive sources and low price. Bamboo based activated carbon obtained through the carbonization and activation of bamboo possesses a high specific surface area and an excellent porous structure, which makes it become a great electrode material for double-layer supercapacitor. Sufficient and base manganese dioxide also has high specific capacity. As a result, the composites from bamboo based activated carbon and manganese dioxide have wide application.Some MnO₂/bamboo-based activated carbon composites with different MnO₂ contents were prepared by mechanical milling method, Chemical method including solid phase method, sol-gel method, co-deposition method. And the composites were used as electrode materials for supercapacitor. The composites were characterized by scanning electron microscope, X-ray diffraction and thermogravimetry-differential scanning calorimetry. Electrochemical performance of the composites with different MnO₂ contents was studied by cyclic voltammetry, alternating current and constant current charge-discharge test in 30% KOH electrolyte.It was found that with an increase of MnO₂ contents, the specific capacitance of composites decreases comparatively in the same current. The composites containing 5%,20%,40% MnO₂ had the similar specific capacitance. When the MnO₂ contents are more than 40%, the specific capacitance of composites reduce sharply. The composite containing 1% MnO₂ had a high specific capacitance of about 338F/g. After 100 charge-discharge cycles, the specific capacitance still maintained 260F/g. The MnO₂ bought wasβ-MnO₂ and particle. MnO₂ prepared by sol-gel method wasγ- MnO₂ and petal shape. Corresponding 1%MnO₂/BC had a high specific capacitance of about 255F/g. After 100 charge-discharge cycles, the specific capacitance still maintained 200F/g. MnO₂ prepared by solid phase method and co-deposition wasα-MnO₂. MnO₂ prepared by solid phase method was particle. 1%MnO₂/BC had a high specific capacitance of about 298F/g. The specific capacitance still maintained 215F/g after 100 charge-discharge cycles. MnO₂ prepared by co-deposition method was nod. 1%MnO₂/BC had a high specific capacitance of about 272F/g. The specific capacitance still maintained 195F/g after 100 charge-discharge cycles. And the nod was wider, when MnO₂ prepared by co-deposition method using ultrasonic. Moreover, the MnO₂/bamboo-based activated carbon supercapacitor electrode composite calcined has higher specific capability.