(桂林理工大學(xué) 化學(xué)與生物工程學(xué)院 廣西礦冶與環(huán)境科學(xué)實驗中心，桂林 541004)
摘 要: 以商業(yè)化V2O5粉體和H2O2為原料，采用溶膠-凝膠法制備了V2O5凝膠，將V2O5凝膠稀釋后進(jìn)行冷凍干燥得到V2O5前驅(qū)體，最后在空氣中450 ℃煅燒2 h得到正交晶系的V2O5樣品。經(jīng)過X射線衍射(XRD)、熱重分析(TGA)和場發(fā)射電子掃描電鏡(FESEM)分析發(fā)現(xiàn)，V2O5前驅(qū)體是具有2D片狀結(jié)構(gòu)的V2O5·nH2O粉體，煅燒后轉(zhuǎn)變?yōu)?D片狀結(jié)構(gòu)的正交晶系V2O5粉體。采用循環(huán)伏安(CV)、電化學(xué)交流阻抗(EIS)和充放電測試研究了V2O5樣品的Li+擴(kuò)散系數(shù)、電化學(xué)反應(yīng)阻抗、倍率性能和電化學(xué)循環(huán)穩(wěn)定性，發(fā)現(xiàn)V2O5樣品的Li+擴(kuò)散系數(shù)和電化學(xué)反應(yīng)阻抗大小與其放電深度密切相關(guān)，所制備的2D片狀V2O5樣品具有較好的倍率性能和優(yōu)異的電化學(xué)循環(huán)穩(wěn)定性。
關(guān)鍵字: 五氧化二釩；溶膠-凝膠法；冷凍干燥；儲鋰性能
（Guangxi Scientific Experiment Center of Mining, Metallurgy and Environment,
College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China）
Abstract:V2O5 gel was prepared by sol-gel method with commercial V2O5 powders and H2O2 as raw materials. Then the V2O5 gel was diluted and freeze-dried to obtain V2O5 precursor. The V2O5 precursor was further treated at 450 °C in air for 2 h to obtain orthorhombic V2O5 sample. X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscope (FESEM) analysis reveal that the precursor is V2O5·nH2O powders with 2D sheet structure, and after calcining in air the V2O5·nH2O powders change into 2D orthorhombic V2O5 powders. Cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge tests were performed to study lithium ion diffusion coefficient, electrochemical reaction impedance, rate performance, and electrochemical cycling stability of the V2O5 sample. The results show that the lithium ion diffusion coefficient and electrochemical reaction impedance are closely related to depth of discharge of the V2O5 sample. The prepared 2D V2O5 sample has good rate performance and excellent electrochemical cycling stability.
Key words: vanadium pentoxide; sol-gel method; freeze-drying; lithium storage performance
