Preparation And Energy Storage Properties Of The Manganese Semiconductor Nanostructure

The energy crisis and environmental pollution is becoming more and more serious,forcing people to study some new energy technologies.Supercapacitor has attracted the attention of researchers owing to its equal status of chemical battery.Supercapacitor has been wildly used in hybrid vehicle,military aerospace,consumer electrons and other filed due to its fast charge/discharge and cycling stability.The key point of the supercapacitor research is still on exploring an electrode material with high capacitance,cycling stability and power density.Manganese is a common electrode material with many valence changes because of its special electron construction.However,Manganese compounds have some shortage such as low conductivity and poor cycling stability which hinder their application as electrode materials for supercapacitors.According to recent studies,experts have found it is an effective mean to improve the electrochemical performace of Mn element through constructing the nanocomposites and heterostructure.Besed on the above points,the main contents are as follows:（1）Zn O/Mn O₂ Nano composite structure has been conducted by taking KMn O₄and Zn（NO₃）₂·6H₂O as raw material through two step hydrothermal synthesis.This nano composite structure shows maximum specific capacitance of 18.1 F g^-1 at the current density of 2 m A cm^-2 and 95%capacitance retention after 50000 cycles.The asymmetric supercapacitor was assembled with the Zn O/Mn O₂ as the positive electrode.This device shows maximum power density of 2159.9 W g^-1 at the energy density of 28.2 Wh g^-1.The capacitance loses 3%after 10000 cycles.（2）Mn₃O₄/Mn S heterostrucure has been fabricated through a facile one step solvothermal synthesis by using（CH₃COO）₂Mn and thiourea as raw material.The as-synthesis heterostrucure delivers the specific capacitance 176.9 F g^-1 at the current density of 2m A cm^-2.After 40000 cycles,the capacitance retention is 68%.The asymmetric supercapacitor device was conducted by using the Mn₃O₄/Mn S heterostrucure as positive electrode shows a power density of 2131.1 W g^-1 at the energy density of 44.4 Wh g^-1 and 80%capacitance retention after 10000 cycles.（3）According to the result of thr First-Principle calculation,the enhancement of the Mn₃O₄/Mn S heterostrucure which sythesied through one-step solvthermal method relys on the interaction of the sulfur and the surface Mn₃O₄ betweent the heterostrucure interface.The energy of shift out one lattice oxygen for Mn₃O₄decreased as well as the band gap became narrowed with the addition of the sulfur.