Safe and efficient polymer electrolyte lithium battery and preparation method thereof

Abstract

The preparation method comprises the following preparation steps: S1, putting a clean small glass bottle into a fuming cupboard, weighing 1.0 g of a PVDF-HFP polymer organic matrix and 0.3-0.4 g of LiTFSI lithium salt, adding the weighed PVDF-HFP polymer organic matrix and the weighed LiTFSI lithium salt into the small glass bottle, adding 4-5mL of an acetonitrile solution serving as a solvent by using a rubber head dropper, covering a bottle cap, sealing the bottle cap by using a sealing adhesive tape, sealing the bottle cap by using a sealing adhesive tape, and magnetically stirring at 70-80 DEG C for 5-6 hours to obtain transparent sol for later use; s2, weighing a mixed plasticizer of 0.15-0.45 g of FEC and 0.15-0.45 g of PC, adding the mixed plasticizer into the transparent sol obtained in the step S1, simultaneously adding 0.3-0.9 g (0.3, 0.6 and 0.9g respectively) of non-flammable ionic liquid [ BMIM ] BF4, and magnetically stirring the mixture for 2-3 hours at the temperature of 70-80 DEG C to obtain light yellow transparent slurry; and S3, observing whether bubbles exist in the slurry or not, if the bubbles exist, carrying out bubble removal treatment, and carrying out standing and heat preservation on the slurry at 70-80 DEG C for 10-20 minutes to remove the bubbles. Compared with a common electrolyte, the safe and efficient polymer electrolyte prepared by the method has the characteristics of safety and non-combustibility.

Description

technical field [0001] The invention relates to the technical field of new energy, in particular to a safe and efficient polymer electrolyte lithium battery and a preparation method thereof. Background technique [0002] In the field of new energy technology, during the charging and discharging process of traditional liquid electrolyte-based lithium-ion batteries, due to the uneven distribution of electric field force, lithium ions will form irregular electrodeposits on the surface of metal lithium. The production of lithium dendrites is a potential safety issue, which not only consumes excessive electrolyte and metal lithium sheets, but also produces excessive side reactions that lead to low Coulombic efficiency (CE), and lithium dendrites have a strong Puncture ability, easy to pierce the separator, and even cause a short circuit inside the battery, there is a risk of thermal runaway, which seriously threatens people's lives. Therefore, inventing safe and efficient electr...

AI Technical Summary

Problems solved by technology

However, [BMIM]BF4, like most other ionic liquids, high-purity ionic liquids tend to have a higher viscosity. In the electrolyte system, the high-viscosity liquid will inhibit the migration of lithium ions, so the electrolyte prepared by using ionic liquids alone tends to be conductive. The efficiency is low, and the price of ionic liquid is expensive. Using a large amount of ionic liquid will easily lead to high production cost of lithium battery, which does not meet the actual market demand.

Images