| Composite polymer electrolytes have been prepared by casting Polyethyleme Oxide(PEO) blendings and lithium bis(oxalato)borate (LiBOB) salt. The performances of LiBOB·(PEO)n polymer electrolytes and LiBOB's conductivity and lithium-ion (Li-ion) transference number were studied by DSC, EIS, Steady-state current, et al. Some cells were made using LiBOB as lithium salt, and their cyclic performances were studied by charge-discharge test. Then 4860110 power Li-ion batteries were made as study objects, using LiMn2O4, LiNi1/3Co1/3Mn1/3O2 and LiFePO4 as cathode active materials, LiBOB as added salt. The current abilities and cyclic performances of different cathode active materials were researched.The results show that the conductive property of LiBOB is excellent, and LiBOB·(PEO)n polymer electrolytes have higher ionic conductivities than LiClO4·(PEO)n. With the increasing of the salt's concentration, LiBOB·(PEO)n's conductivities increase first, then decrease. When the molecule ratio of O/Li is 16:1, the polymer electrolyte has the maximal conductivityσ=5.8×10-6S/cm at room temperature, and the ionic transference number of Li+ is 0.39. With the rising of temperature, the polymer electrolyte's conductivity increases. When the temperature range is controlled to 30-80℃, the conductivity increases from 10-7S/cm to 10-3S/cm, improved by four magnitudes.The polymer electrolytes' crystallizabilities decrease with the increasing of the salt's concentration. The addition of LiBOB decreases PEO's melting temperature, which can be reduced from pure PEO's 70℃to 50℃when O/Li is 16:1. LiBOB can shape steady and effective SEI membrane at the graphite anode. The cells perform well at 0.25C current, and the discharge capacity can keep at 91.20% after 50 cycles. Though the capacities have some attenuations at 0.5C and 1C rate, the cyclic performance is still very good at 0.5C rate.The power Li-ion batteries' current abilities and cyclic performances are strongly influenced by cathode active materials. LiMn2O4-LiNi1/3Co1/3Mn1/3O)2 compound cathode active materials have better performances than LiMn2O4 material, and the more the proportion of LiNi1/3Co1/3Mn1/3O2, the better the cells' cyclic performances. When the mass proportion of LiMn2O4-LiNi1/3Co1/3Mn1/3O2 is 1:1, the discharge capacity can keep at 96.71% at 1C rate after 100 cycles. While the mass is 3:1, it has When LiFePO4 is used as cathode active material, the cells have quite steady discharge flats at low current and excellent cyclic performances. After 100 cycles, the discharge capacity which is 17.14Ah nearly has discrease at 1C charge-discharge current. After 1000 cycles, the cell's discharge capacity is 14.13Ah, keeping at 81.63%. As the current increasing remarkably, the cells' capacities have observably decreases. The discharge capacity keeps at 93.58% at 1.5C rate, and the voltage flat is probably 2.98V.
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