(1. 中南大學 化學化工學院，長沙 410083；
2. 中國科學院 清潔能源前沿研究重點實驗室，北京 100190)
摘 要: 以V2O5、H3PO4為原料，在V2O5與H3PO4摩爾比為1:2.4條件下通過水熱法制備VOPO4•xH2O，得到的VOPO4•xH2O再通過650 ℃煅燒制備納米結構ε-VOPO4，通過X射線衍射對制備材料進行表征。采用SEM對產物形貌進行觀察，考察原料配比條件對產物組成和晶相的影響；對納米ε-VOPO4進行電化學性能測試。結果表明：在該條件下制備出的納米ε-VOPO4物相純；所制備納米結構的ε-VOPO4顆粒粒徑為200 nm，且顆粒度均勻；在0.2C倍率、電壓范圍為2.0~4.3 V充放電制度下，首次充電比容量可以達到227.9 mA•h/g, 在0.5C倍率充放電制度下循環(huán)140次后，放電容量達160.49 mA•h/g。
關鍵字: ε-VOPO4；正極材料；鋰離子電池；電化學性能
（1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing 100190, China）
Abstract:VOPO4•xH2O was obtained through hydro-thermal method with V2O5 and H3PO4 as initial materials. Nanostructured ε-VOPO4 was synthesized from VOPO4•xH2O heated at 650 ℃ when molar ratio of V2O5 to H3PO4 is 1:2.4. The nanostructed ε-VOPO4 has been characterization by X-ray. The product morphology was studied by SEM. The results show that the nanostructured ε-VOPO4 is pure with particle size of about 200 nm. The effects of the molar ratio of the initial reaction materials on the product components and crystal structure were studied. And the electrochemical performance of the nanostructured ε-VOPO4 was also studied. The best electrochemical performance and crystal of the obtained nanostructured ε-VOPO4 is from that molar ratio of the V2O5 and H3PO4 is 1:2.4. The particle size of the nanostructured ε-VOPO4 was about 200 nm. The nanostructured ε-VOPO4 exhibits an initial discharge capacity of 227.9 mA•h/g at 0.2C rate in the voltage window of 2.0-4.3 V. The discharge capacity is as high as 160.49 mA•h/g at the rate of 0.5C after the 140th cycle.
Key words: ε-VOPO4; cathode material; lithium battery; electrochemical characteristics
