Lithium iron phosphate （LiFePO4） doped with magnesium was hydrothermally synthesized from commercial LiOH, FeSO4, H3PO4 and MgSO4 with glucose as carbon precursor in aqueous solution. The samples were characterized ...Lithium iron phosphate （LiFePO4） doped with magnesium was hydrothermally synthesized from commercial LiOH, FeSO4, H3PO4 and MgSO4 with glucose as carbon precursor in aqueous solution. The samples were characterized by X-ray powder diffraction, scanning electron microscopy and constant charge-discharge cycling. The results show that the synthesized powders have been in situ coated with carbon precursor produced from caramel reaction of glucose. At ambient temperature （28±2℃）, the electrochemical performances of LiFePO4 prepared exhibit the high discharge capacity of 135 mAh g^-1 at 5C and good capacity retention of 98% over 90 cycles. The excellent electrochemical performances should be correlated with the intimate contact between carbon and LiFePO4 primary and secondary particles, resulting from the in situ formation of carbon precursor/carbon, leading to the increase in conductivity of LiFePO4.展开更多
以一水柠檬酸和六水硝酸钴为原料,采用水热-碳化联合法制备碳包覆纳米金属钴催化剂。通过调变原料比例和碳化温度,得到优选催化剂Co-CA_(2.5)-500。将制备的催化剂用于肉桂醛选择加氢反应,表现出优异的催化性能,在70℃、2 MPa H_(2)条件...以一水柠檬酸和六水硝酸钴为原料,采用水热-碳化联合法制备碳包覆纳米金属钴催化剂。通过调变原料比例和碳化温度,得到优选催化剂Co-CA_(2.5)-500。将制备的催化剂用于肉桂醛选择加氢反应,表现出优异的催化性能,在70℃、2 MPa H_(2)条件下,以9 mL EtOH+1 mL H_(2)O为溶剂反应2 h,肉桂醛转化率为75.1%,肉桂醇选择性为64.7%。表征结果表明,Co-CA_(2.5)-500的高催化性能与碳载体发达的孔道结构和活性金属钴的高度分散有关。展开更多
为改善磷酸钒锂的导电性能,以柠檬酸为碳源,采用溶胶凝胶法合成碳包覆磷酸钒锂(LVP/C)复合材料。通过充放电性能测试、循环伏安测试、XRD、SEM等分析手段,探讨碳含量对复合材料电化学性能的影响。结果表明:碳源加入摩尔比为2.0时所制得...为改善磷酸钒锂的导电性能,以柠檬酸为碳源,采用溶胶凝胶法合成碳包覆磷酸钒锂(LVP/C)复合材料。通过充放电性能测试、循环伏安测试、XRD、SEM等分析手段,探讨碳含量对复合材料电化学性能的影响。结果表明:碳源加入摩尔比为2.0时所制得的LVP/C材料电化学性能最好。在电压3.0~4.3 V、0.5倍率的条件下,C2.0材料首次放电比容量可达123 m Ah/g,循环80周后,相对于第一周循环充放电容量,比容量保持率为99.7%,材料的可逆性和锂离子扩散性能最好。结构和形貌表征显示样品结晶性能良好,晶粒大小约1μm,碳层厚度约为3.6 nm。展开更多
文摘Lithium iron phosphate （LiFePO4） doped with magnesium was hydrothermally synthesized from commercial LiOH, FeSO4, H3PO4 and MgSO4 with glucose as carbon precursor in aqueous solution. The samples were characterized by X-ray powder diffraction, scanning electron microscopy and constant charge-discharge cycling. The results show that the synthesized powders have been in situ coated with carbon precursor produced from caramel reaction of glucose. At ambient temperature （28±2℃）, the electrochemical performances of LiFePO4 prepared exhibit the high discharge capacity of 135 mAh g^-1 at 5C and good capacity retention of 98% over 90 cycles. The excellent electrochemical performances should be correlated with the intimate contact between carbon and LiFePO4 primary and secondary particles, resulting from the in situ formation of carbon precursor/carbon, leading to the increase in conductivity of LiFePO4.
文摘以一水柠檬酸和六水硝酸钴为原料,采用水热-碳化联合法制备碳包覆纳米金属钴催化剂。通过调变原料比例和碳化温度,得到优选催化剂Co-CA_(2.5)-500。将制备的催化剂用于肉桂醛选择加氢反应,表现出优异的催化性能,在70℃、2 MPa H_(2)条件下,以9 mL EtOH+1 mL H_(2)O为溶剂反应2 h,肉桂醛转化率为75.1%,肉桂醇选择性为64.7%。表征结果表明,Co-CA_(2.5)-500的高催化性能与碳载体发达的孔道结构和活性金属钴的高度分散有关。
文摘为改善磷酸钒锂的导电性能,以柠檬酸为碳源,采用溶胶凝胶法合成碳包覆磷酸钒锂(LVP/C)复合材料。通过充放电性能测试、循环伏安测试、XRD、SEM等分析手段,探讨碳含量对复合材料电化学性能的影响。结果表明:碳源加入摩尔比为2.0时所制得的LVP/C材料电化学性能最好。在电压3.0~4.3 V、0.5倍率的条件下,C2.0材料首次放电比容量可达123 m Ah/g,循环80周后,相对于第一周循环充放电容量,比容量保持率为99.7%,材料的可逆性和锂离子扩散性能最好。结构和形貌表征显示样品结晶性能良好,晶粒大小约1μm,碳层厚度约为3.6 nm。
