电解液锂盐浓度对磷酸铁锂电化学性能的影响

研究了LiPF_6浓度对PC/EC混合溶剂电解液的电导率、可燃性的影响,考察了LiFePO_4电极在不同LiPF_6浓度的电解液中的电化学性质。结果表明,电解液的电导率和可燃性受LiPF_6的浓度影响很大,LiFePO_4电极的倍率性质和循环稳定性随电解液中LiPF_6浓度的升高而升高,特别是在60℃高温条件下,LiFePO_4电极表现出优异的高温循环稳定性,产生这种现象的主要原因是高浓度锂盐电解液有助于降低电解液内部的浓差极化现象,抑制电极/电解液表面的副反应,铝箔的腐蚀也得到了抑制。

Effect of lithium salt concentration in electrolyte on electrochemical properties of lithium iron phosphate cathode

The influence of LiPF6 concentration on the conductivity and flammability of the electrolyte based on PC/EC mixing solvent was investigated.The electrochemical properties of LiFePO4 cathode in the electrolyte of different LiPF6 concentrations were determined.The results show that the conductivity and flammability of the electrolyte are significantly affected by the LiPF6 concentration.The rate performance and cycling performance of LiFePO4 cathode enhance with LiPF6 concentration increasing.An excellent cycling performance at 60 ℃ is achieved when the LiPF6 concentration is higher than 2.0 mol/L.The main reason for the enhancement of high rate performance and cycling stability is due to the decrease of concentration polarization of the electrolyte with high salt concentration.Side reactions at the electrode/electrolyte interface and the corrosion of aluminum foil are also suppressed.