Quick-charging high-temperature-resistant electrolyte and preparation method thereof

Abstract

The invention discloses a quick-charging high-temperature-resistant electrolyte and a preparation method thereof. The quick-charging high-temperature-resistant electrolyte comprises hexadecyl trimethyl ammonium, butyl trimethyl ammonium, lithium bis(oxalato) borate, a solvent and an additive, wherein the solvent comprises EC, DEC and PC, and the electrolyte comprises the following solvents in percentage by mass: 25-29% of EC, 37-45% of DEC and 6-8% of PC; the additive is one or both of VC or PS; wherein the concentration of the lithium bis(oxalato) borate in the electrolyte is 0.45+ / -0.1 mol / L. According to the invention, hexadecyl trimethyl ammonium, butyl trimethyl ammonium and lithium bis(oxalato) borate are adopted to replace traditional LiPF6 as an electrolyte, the electrolyte is a liquid organic salt completely composed of anions and cations at room temperature, the electrolyte has electrical conductivity, the decomposition voltage is higher than that of a conventional electrolyte, and the electrolyte is non-volatile and non-flammable in a wide temperature range; the electrolyte is high in conductivity and good in mechanical property, and due to the fact that the phenomena ofsolvent volatilization, liquid leakage and the like are avoided, the safety and stability of the battery can be improved; tests show that the lithium ion polymer battery adopting the electrolyte provided by the invention can meet the requirement of 5C quick charging.

Description

technical field [0001] The invention relates to the field of lithium battery preparation, in particular to a fast-charging high-temperature resistant electrolyte and a preparation method. Background technique [0002] Lithium-ion battery is a secondary battery (rechargeable battery) that mainly relies on the movement of lithium ions between the positive and negative electrodes to work. During the charging and discharging process, Li+ intercalates and deintercalates back and forth between the two electrodes: when charging, Li+ is deintercalated from the positive electrode, intercalated into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. [0003] Traditional polymer lithium batteries are classified into conventional capacity batteries, high temperature batteries and rate batteries, etc. Conventional batteries can only be realized in terms of capacity density, but fast charging of hig...

AI Technical Summary

Problems solved by technology

[0003] Traditional polymer lithium batteries are classified into conventional capacity batteries, high temperature batteries and rate batteries, etc. Conventional batteries can only be realized in terms of capacity density, but fast charging of high current charging methods cannot be realized, only Support 0.5 ~ 1C small rate charging mode, charging time is relatively long; high temperature battery is to support the normal operation of the battery at a temperature above 80 degrees, the battery will not be swollen, but at room temperature or low temperature, due to the electrolyte used The selected solvent has the characteristics of high boiling point, high viscosity, and small relative dielectric constant. The internal resistance of the battery is relatively large, which cannot support high-current charging and discharging.

The rate battery is a battery that supports the discharge of a large battery. Due to the low boiling point of the solvent used in the electrolyte, low viscosity, large relative permittivity, and high conductivity, the internal resistance of the battery is relatively small, and the pole piece needs a larger ratio. The contact area, the separator needs a larger porosity, and the energy density of the battery is relatively low

Therefore, the compatibility between the performance of conventional ordinary batteries and the performance of fast charging is relatively poor. Under high temperature conditions, the rate battery and fast charging technology cannot be combined.

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