The Preparation Of The Metal Oxide And Its Compound And The Performance Research Of The Supercapacitors

Supercapacitors fill effectively the gap between the traditional capacitor and battery.It not only has high energy density,but also has high power density.Meanwhile it has fast charge-discharge rate and long cycle life.The key factors that has great influence on the performance of the supercapacitor are the choice of material.Among them,metal oxides have been studied more and more due to their high specific capacitance and high chemical activity.However,the semiconductor properties of metal oxides restrict their electrical conductivity,resulting in the decrease of active sites and the increase of internal resistance of the material,which directly leads to the decrease of specific capacitance and rate performance.Therefore,it is very important to choose the proper electrode material and design the reasonable microstructure.In this paper,in order to improve the reduction of the specific capacitance caused by insufficient conductivity,cross-linked nanoporous CuO was successfully prepared,which had bamboo leaf-like structures.The electrochemical results showed that the specific capacitance of the CuO electrode was 251.5 F g^-1 at 0.25 A g^-1.After storage in vacuum for 10 weeks,the specific capacitance was 269.6 F g^-1 at the same current density.After cycling 500s at 2 A g^-1,the specific capacitance could still maintain 88.79%.These tests show that the CuO electrode had high mass specific capacitance and nice stability,but there is still a large gap from the actual application.Then,in order to solve the problem that the common in-situ growth method is difficult to grow uniformly and densely,a novel two-dimensional ultrathin NiCo₂O₄nanosheet array was in-situ grown by the suspension method.The electrochemical results showed that the electrode had a maximum specific capacitance of 2017.78 F g^-1 at 1 A g^-1.Even at 30 A g^-1,the specific capacitance still reached 1880.00 F g^-1.The corresponding rate performance was 93.17%.After cycling 5000 times at 10 A g^-1,the capacitance retention rate could still maintain as 90.91%.All above results showed that 2D-ultrathin NiCo₂O₄ nanosheets arrays had high mass specific capacitance and superior rate capability.The results showed that NiCo₂O₄ was the most potential electrode material.In order to further improve the performance of NiCo₂O₄.This article innovatively used wipes fibers as sacrificial templates and carbon resource to synthesize the hollow microtubes compound assembled with carbon and ultrathin NiCo₂O₄ nanosheets arrays.The electrochemical results showed that the electrode had a maximum specific capacitance of 3070 F g^-1 at 0.5 A g^-1,which reached 86%of the theoretical specific capacitance.Even at 50 A g^-1,the specific capacitance still reached 3070 F g^-1.The corresponding rate performance was 85%.After cycling 5000 times at 30 A g^-1,the capacitance retention rate could still maintain as 96%,the loss rate was only 3.79%.These excellent properties showed that the combination with carbon can significantly compensate for the shortcoming of conductivity of metal oxides.