Guocong Liu

Synthesis and characterization of Sm3+-doped CeO2 powders

Abstract Sm 3+ -doped CeO 2 (denoted as Ce 1– x Sm x O 2 ) powders with different morphologies were successfully synthesized via a precursor-growth-calcination approach, in which precursor was first synthesized by a hydrothermal method and Ce 1– x Sm x O 2 powders were finally obtained through a calcination process. The products were characterized with X-ray diffractometry(XRD), field emission scanning electron microscopy(FE-SEM) and fluorescence spectroscopy. The results reveal that the Ce 1– x Sm x O 2 powders obtained by calcining the precursors prepared in the absence and presence of poly(vinyl pyrrolidone) (PVP) exhibit bundle- and sphere-like morphology, respectively. The possible growth process was proposed by preparing a series of intermediate morphologies during the shape evolution of CeO 2 based on the SEM image observation. It is also found that the luminescence intensity of bundle-like Ce 1– x Sm x O 2 is enhanced in comparison with that of sphere-like one due to its special morphology.

Grinding–sol–gel synthesis and electrochemical performance of mesoporous Li3V2(PO4)3 cathode materials

Abstract Li 3 V 2 (PO 4 ) 3 precursor was obtained with V 2 O 5 · n H 2 O, LiOH·H 2 O, NH 4 H 2 PO 4 and sucrose as starting materials by grinding-sol-gel method, and then the monoclinic-typed Li 3 V 2 (PO 4 ) 3 cathode material was prepared by sintering the amorphous Li 3 V 2 (PO 4 ) 3 . The as-sintered samples were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption-desorption and electrochemical measurement. It is found that Li 3 V 2 (PO 4 ) 3 sintered at 700 °C possesses good wormhole-like mesoporous structure with the largest specific surface area of 188 cm 2 /g, and the smallest pore size of 9.3 nm. Electrochemical test reveals that the initial discharge capacity of the 700 °C sintered sample is 155.9 mA·h/g at the rate of 0.2 C , and the capacity retains 154 mA·h/g after 50 cycles, exhibiting a stable discharge capacity at room temperature.

Sol-Gel Synthesis and Electrochemical Performance of Li 3 V 2-2x/3 Mn x (PO 4 ) 3 Cathode Material for Lithiumion Batteries: Sol-Gel Synthesis and Electrochemical Performance of Li 3 V 2-2x/3 Mn x (PO 4 ) 3 Cathode Material for Lithiumion Batteries

以CH 3 COOLi·2H 2 O、V 2 O 5 、Mn(CH 3 COO) 2 ·4H 2 O、(NH 4 ) 2 HPO 4 和蔗糖为原料, 采用溶胶–凝胶法合成了掺锰磷酸钒锂/碳(Li 3 V 2-2 x /3 Mn x (PO 4 ) 3 /C)复合正极材料, 用XRD、XPS、SEM、电化学性能对样品进行了表征. 测试结果表明, 少量锰的掺杂并未改变Li 3 V 2 (PO 4 ) 3 /C的单斜结构, Li 3 V 1.94 Mn 0.09 (PO 4 ) 3 中的Mn和V分别以+2和+3价存在, 其颗粒类似球形, 直径比较均匀且小于200 nm, 并表现出良好的电化学性能. 在0.1 C 倍率和3.0~4.8 V电压内, 该样品的首次充、放电容量分别为182.1和168.8 mAh/g, 放电效率高达92.69%, 而且100次循环后, 其放电比容量仍是首次放电容量的77.4%.以CH 3 COOLi·2H 2 O、V 2 O 5 、Mn(CH 3 COO) 2 ·4H 2 O、(NH 4 ) 2 HPO 4 和蔗糖为原料, 采用溶胶–凝胶法合成了掺锰磷酸钒锂/碳(Li 3 V 2-2 x /3 Mn x (PO 4 ) 3 /C)复合正极材料, 用XRD、XPS、SEM、电化学性能对样品进行了表征. 测试结果表明, 少量锰的掺杂并未改变Li 3 V 2 (PO 4 ) 3 /C的单斜结构, Li 3 V 1.94 Mn 0.09 (PO 4 ) 3 中的Mn和V分别以+2和+3价存在, 其颗粒类似球形, 直径比较均匀且小于200 nm, 并表现出良好的电化学性能. 在0.1 C 倍率和3.0~4.8 V电压内, 该样品的首次充、放电容量分别为182.1和168.8 mAh/g, 放电效率高达92.69%, 而且100次循环后, 其放电比容量仍是首次放电容量的77.4%.