Non-aqueous electrolyte solution and lithium-ion battery using same

Abstract

The invention belongs to the field of lithium-ion batteries, and particularly relates to a non-aqueous electrolyte solution and a lithium-ion battery using the same. The non-aqueous electrolyte solution comprises a non-aqueous organic solvent, lithium salts and additives; the non-aqueous organic solvent comprises at least one cyclic lactone compound; the additives comprise at least a negative electrode film-forming additive and at least a positive electrode passivation protective agent; and the positive electrode passivation positive agent is selected from at least one of 3,4-ethylenedioxythiophene, a cyclic anhydride phosphonate compound and a nitrile compound. The reduction potential of the negative electrode film-forming additive in the non-aqueous electrolyte solution is higher than that of the cyclic lactone compound, and a steady negative electrode passivation film can be formed; the positive electrode passivation protective agent can suppress oxygenolysis of the cyclic lactone compound at the positive electrode, so that the overcharging performance of the lithium-ion battery not only can be improved, but the cycle performance of the battery is also not affected.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a nonaqueous electrolytic solution and a lithium ion battery using the nonaqueous electrolytic solution. Background technique [0002] Lithium-ion batteries are widely used in consumer electronics products, energy storage and power batteries due to their advantages such as high specific energy, long cycle life, and small self-discharge. With the widespread application of lithium-ion batteries, their use environments have long tended to be diverse, and the requirements for battery safety performance are getting higher and higher. For example, in order to ensure the charging safety of electronic products, batteries are required to have higher anti-overcharge performance. [0003] Studies have shown that the cyclic lactone compound significantly improves the overcharge performance of the battery due to its oxidation potential lower than that of conventional carbonat...

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Problems solved by technology

[0003] Studies have shown that the cyclic lactone compound significantly improves the overcharge performance of the battery due to its oxidation potential lower than that of conventional carbonates and the oxidation reaction forms an insulating layer on the surface of the positive electrode to block the current, but due to its high reduction potential affects EC, FEC etc. form a highly resistive and unstable negative passivation film (SEI), which affects the cycle performance of the battery (Journal of powersources, 2008, 183, 755-760)

Moreover, the oxidation potential of the cyclic lactone compound is also lower than that of conventional carbonates. During the cycle, it will be oxidized at the positive electrode, and the product will increase the impedance of the battery and affect the cycle performance of the battery.

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