High dispersed carbon black was applied for LiFePO4 cathodes as conductive agent.Nano-conductive carbon agent was pre-dispersed with poly acrylic acid(PAA) as dispersant in organic N-methyl-pyrrolidone(NMP) solvent sy...High dispersed carbon black was applied for LiFePO4 cathodes as conductive agent.Nano-conductive carbon agent was pre-dispersed with poly acrylic acid(PAA) as dispersant in organic N-methyl-pyrrolidone(NMP) solvent system.The dispersion property of nano-conductive carbon agent was evaluated using particle size distribution measurements,scanning electron microscopy(SEM) and transmission electron microscope(TEM).LiFePO4 cathode with as-received nano-conductive carbon agent(SP) and LiFePO4 cathode with pre-dispersed nano-conductive carbon agent(SP-PAA) were examined by scanning electron microscopy(SEM),cyclic voltammetry(CV),electrochemical impendence spectroscopy(EIS) and charge/discharge cycling performance.Results show that the dispersion property of carbon black is improved by using PAA as the dispersant.The LiFePO4 cathodes with SP-PAA exhibit improved rate behaviors(4C,135.1 mAh/g) and cycle performance(95%,200 cycles) compared to LiFePO4 cathodes with SP(4C,103.9 mAh/g and 83%,200 cycles).Because pre-dispersed carbon black(SP-PAA) is dispersed homogeneously in the dried composite electrode to form a more uniform conductive network between the active material particles,electrochemical performances of the LiFePO4 cathodes are improved.展开更多
The influence of thermomechanical aging on microstructure and mechanical properties of 2519A aluminum alloy was investigated by means of microhardness test,tensile test,optical microscopy (OM) and transmission electro...The influence of thermomechanical aging on microstructure and mechanical properties of 2519A aluminum alloy was investigated by means of microhardness test,tensile test,optical microscopy (OM) and transmission electron microscopy (TEM).The results show that 50% cold rolling deformation prior to aging is beneficial since it promotes a more homogeneous distribution of the precipitation phase and reduces the number of precipitation phase on the grain boundaries,and thus shrinks the total volume of precipitation-free zones at grain and sub-grain boundaries.As a result,the tensile properties of 2519A aluminum alloy have been significantly improved.展开更多
基金Project(51204211) supported by the National Natural Science Foundation of ChinaProject(2012M521543) supported by the China Postdoctoral Science Foundation
文摘High dispersed carbon black was applied for LiFePO4 cathodes as conductive agent.Nano-conductive carbon agent was pre-dispersed with poly acrylic acid(PAA) as dispersant in organic N-methyl-pyrrolidone(NMP) solvent system.The dispersion property of nano-conductive carbon agent was evaluated using particle size distribution measurements,scanning electron microscopy(SEM) and transmission electron microscope(TEM).LiFePO4 cathode with as-received nano-conductive carbon agent(SP) and LiFePO4 cathode with pre-dispersed nano-conductive carbon agent(SP-PAA) were examined by scanning electron microscopy(SEM),cyclic voltammetry(CV),electrochemical impendence spectroscopy(EIS) and charge/discharge cycling performance.Results show that the dispersion property of carbon black is improved by using PAA as the dispersant.The LiFePO4 cathodes with SP-PAA exhibit improved rate behaviors(4C,135.1 mAh/g) and cycle performance(95%,200 cycles) compared to LiFePO4 cathodes with SP(4C,103.9 mAh/g and 83%,200 cycles).Because pre-dispersed carbon black(SP-PAA) is dispersed homogeneously in the dried composite electrode to form a more uniform conductive network between the active material particles,electrochemical performances of the LiFePO4 cathodes are improved.
基金Project(2005CB623706) supported by the National Basic Research Program of China
文摘The influence of thermomechanical aging on microstructure and mechanical properties of 2519A aluminum alloy was investigated by means of microhardness test,tensile test,optical microscopy (OM) and transmission electron microscopy (TEM).The results show that 50% cold rolling deformation prior to aging is beneficial since it promotes a more homogeneous distribution of the precipitation phase and reduces the number of precipitation phase on the grain boundaries,and thus shrinks the total volume of precipitation-free zones at grain and sub-grain boundaries.As a result,the tensile properties of 2519A aluminum alloy have been significantly improved.
