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MnO2为有前景的超级电容器正极材料,具有较高的理论比电容及良好的循环稳定性,但电子电导性不佳限制了其应用。采用一步水热法制备了还原氧化石墨烯(RGO)/NixMn1-x/2O2复合材料。通过XRD、SEM、TEM、FTIR、电化学分析等手段对制备的RGO/NixMn1-x/2O2物相组成、微观形貌和电化学性能进行了表征和分析。电化学测试结果表明:Ni元素的引入提高了MnO2的电容性能,以水热法制备的MnO2的比电容为66 F/g(扫描速度10m V/s),而Ni元素掺杂量x=0.02时,Ni0.02Mn0.99O2比电容为111 F/g;材料中引入RGO后,RGO/NixMn1-x/2O2复合材料电容性能进一步提高,加入2wt%的RGO时,RGO/Ni0.02Mn0.99O2的比电容为136 F/g。RGO的引入提高了活性材料的电子迁移速率,Ni元素的掺杂造成了MnO2晶格中存在着适量的点缺陷,提高了其导电性。以RGO/NixMn1-x/2O2为正极的超级电容器可同时具备双电层电容器与赝电容器的优点,以Ni掺杂MnO2和RGO的负载协同提高该复合材料电化学性能。
MnO2 is a promising supercapacitor cathode material with high theoretical specific capacitance and good cycling stability, but its poor electrical conductivity limits its application. Reduced graphene oxide (RGO) / NixMn1-x / 2O2 composites were prepared by one-step hydrothermal method. The phase composition, morphology and electrochemical properties of RGO / NixMn1-x / 2O2 were characterized and analyzed by XRD, SEM, TEM, FTIR and electrochemical analysis. The results of electrochemical tests showed that the introduction of Ni element increased the capacitance of MnO2. The specific capacitance of MnO2 prepared by hydrothermal method was 66 F / g (scan rate of 10 mV / s), while the Ni element doping amount was 0.02 , The specific capacitance of Ni0.02Mn0.99O2 is 111 F / g. The RGO / NixMn1-x / 2O2 composites have further improved the capacitance when RGO is introduced into the material. When 2wt% RGO is added, the RGO / Ni0.02Mn0.99O2 The specific capacitance is 136 F / g. The introduction of RGO improves the electron transfer rate of the active material. The doping of Ni element results in the existence of some defects in the MnO2 lattice and enhances its conductivity. The supercapacitors with RGO / NixMn1-x / 2O2 as the positive electrode can have the advantages of electric double layer capacitors and pseudocapacitors. The Ni-doped MnO2 and RGO loads synergistically improve the electrochemical performance of the composites.