LiFe Mn1-xPO4/C composites were synthesized by a solid-state reaction route using phenolic resin as both reducing agent and carbon source. The effect of Fe doping on the crystallinity and electrochemical performance o...LiFe Mn1-xPO4/C composites were synthesized by a solid-state reaction route using phenolic resin as both reducing agent and carbon source. The effect of Fe doping on the crystallinity and electrochemical performance of LiFexMnt xPOJC was investigated. The experimental results show that the Fe2＋ substitution for Mn2＋ will lead to crystal lattice shrinkage of LiFe Mn1-xPO4/C particles due to the smaller ionic radii of Fe2＋ In the investigated Fe doping range （x = 0 to 0.7）, LiFe Mn1-xPO4/C （x = 0.4） composites exhibited a maximum discharge capacity of 148.8 mAh/g at 0.1 C while LiF%MnI_xPO4/C （x = 0.7） composite showed the best cycle capability with a capacity retention ratio of 99.0% after 30 cycles at 0.2 C. On the contrary, the LiFe Mnl-xPO4/ C （x = 0.5） composite performed better trade-off on discharge capacity and capacity retention ratio, 127.2 mAh/ g and 94.7% after the first 30 cycles at 0.2 C, respectively, which is more preferred for practical applications.展开更多
In this study,sub-micrometer LiFePO_4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries.Experimental results show t...In this study,sub-micrometer LiFePO_4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries.Experimental results show that templates and calcination time have significant impacts on the purity,particle size and morphology of LiFePO_4 particles.The as-prepared LiFePO_4 particles using polyvinyl pyrrolidone(PVP) template with additional one hour calcination at 700℃exhibit characteristics of good crystallinity,uniform size distribution,high capacity and cycling performance.The specific discharge capacities of 141.2 and 114.0mA·h/g were obtained at the charge/discharge rates of 0.1 and 1.0 C,respectively.It retained 96.0%of an initial capacity after 100 cycles at 1.0 C rate.The good electrochemical performance of the as-synthesized material is attributed to the synergistic factors of its reasonable particle size and surface areas and high crystallinity.展开更多
基金Funded by the Applied Basic Research Special Program of Guangzhou City(No.7411793079907)the Guangdong Province Science&Technology Bureau(Nos.2012B091100351,2012B050300004)the National Natural Science Foundation of China(No.21376035)
文摘LiFe Mn1-xPO4/C composites were synthesized by a solid-state reaction route using phenolic resin as both reducing agent and carbon source. The effect of Fe doping on the crystallinity and electrochemical performance of LiFexMnt xPOJC was investigated. The experimental results show that the Fe2＋ substitution for Mn2＋ will lead to crystal lattice shrinkage of LiFe Mn1-xPO4/C particles due to the smaller ionic radii of Fe2＋ In the investigated Fe doping range （x = 0 to 0.7）, LiFe Mn1-xPO4/C （x = 0.4） composites exhibited a maximum discharge capacity of 148.8 mAh/g at 0.1 C while LiF%MnI_xPO4/C （x = 0.7） composite showed the best cycle capability with a capacity retention ratio of 99.0% after 30 cycles at 0.2 C. On the contrary, the LiFe Mnl-xPO4/ C （x = 0.5） composite performed better trade-off on discharge capacity and capacity retention ratio, 127.2 mAh/ g and 94.7% after the first 30 cycles at 0.2 C, respectively, which is more preferred for practical applications.
基金the Fundamental Research Funds for the Central Universities of China(No.DUT11NY08)
文摘In this study,sub-micrometer LiFePO_4 particles with high purity and crystallinity were synthesized using supercritical hydrothermal method as the cathode material for lithium ion batteries.Experimental results show that templates and calcination time have significant impacts on the purity,particle size and morphology of LiFePO_4 particles.The as-prepared LiFePO_4 particles using polyvinyl pyrrolidone(PVP) template with additional one hour calcination at 700℃exhibit characteristics of good crystallinity,uniform size distribution,high capacity and cycling performance.The specific discharge capacities of 141.2 and 114.0mA·h/g were obtained at the charge/discharge rates of 0.1 and 1.0 C,respectively.It retained 96.0%of an initial capacity after 100 cycles at 1.0 C rate.The good electrochemical performance of the as-synthesized material is attributed to the synergistic factors of its reasonable particle size and surface areas and high crystallinity.
