水热法制备α-MoO_3煅烧对其结构、电容性能影响研究

Effect of Calcining on Structure and Capacitance Properties of α-MoO_3 Prepared by Hydrothermal Method

以钼酸铵和浓硝酸为原料,采用一步水热法成功制备了α-MoO_3。通过Raman、FT-IR、XRD、FESEM探究了600℃煅烧对α-MoO_3结构、形貌的影响。用循环伏安法(CV)、恒流充放电(GCD)和电化学阻抗谱(EIS)对煅烧前后α-MoO_3的电容特性进行研究。结果表明:煅烧后α-MoO_3的粒径和晶面间距变大,Mo-O键的极化率和粒子的结晶度提高。煅烧后α-MoO_3的电荷转移电阻较煅烧前明显减小(Rct=1.6Ω),且表现出更加明显的赝电容特性。以0.5 mol·L^(-1) Li2SO4为电解液,在0.5 A·g^(-1)的电流密度下,煅烧后α-MoO_3的比电容较煅烧前提高了100.5%,达到163.56 F·g^(-1)。由煅烧后α-MoO_3制备的电极经1 000次循环,电容保持率为87.5%,表现出好的循环稳定性。

Using ammonium molybdate and concentrated nitric acid as raw materials, α-MoO3 was successfully prepared by one-step hydrothermal method and calcined in a muffle furnace at 600℃. The effects of calcination on the structure and morphology of α-MoO3 were investigated using Raman, FT-IR, XRD and FESEM. The capacitance properties of α-MoO3 before and after calcination were studied by cyclic voltammetry （CV）, galvanostatic charge- discharge （GCD） and electrochemical impedance spectroscopy （EIS）. The results showed that the particle size and interplanar spacing of α-MoO3 became larger, the polarizability of Mo-O bond and the crystallinity of the particles increased after calcination. After calcined, the charge transfer resistance of α-MoO3 was significantly reduced （Rct= 1.6） compared with that before calcination, and the pseudocapacitance properties were more pronounced. With 0.5 M Li2SO4 as electrolyte, the specific capacitance of α-MoO3 after calcination was 100.5% higher than that before calcination, reaching 163.56 F·g-1, at a current density of 0.5 A·g-1. The electrode prepared from calcined α-MoO3 was subjected to 1000 cycles, and the capacitance retention rate was 87.5%, showing good cycle stability.