A kind of lithium ion battery electrolyte and preparation method thereof

Abstract

The invention provides a lithium-ion battery electrolyte and a preparation method thereof, belonging to the technical field of lithium-ion batteries. In the commercial electrolyte, the present invention directly introduces lithium-modified inorganic layered materials and high molecular polymers with ion conductivity, and the lithium-friendly inorganic layered materials and high molecular polymers directly participate in the solid electrolyte membrane (SEI) on the surface of lithium metal negative electrodes. ) reconstruction, a strong lithium negative electrode, to achieve the effect of inhibiting the growth of lithium metal dendrites, and the lithium-friendly material of the present invention will not be consumed over time, and can stabilize the lithium metal negative electrode for a long time. The lithium-modified inorganic layered material provided by the present invention has strong mechanical properties, strong thermal stability and flame retardancy, greatly improving the safety performance of the battery, and the inorganic layered material required by the present invention and High molecular polymer materials are industrial raw materials, and their cost is extremely low, which is compatible with the industrial production of lithium battery electrolyte.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery electrolyte for suppressing lithium dendrites and a preparation method thereof. Background technique [0002] With the continuous increase of human demand for energy and the excessive grabbing of fossil energy, oil resources are becoming increasingly depleted and environmental problems are becoming increasingly severe, seriously affecting the development of the world economy and the survival of human beings, making people's demand for new energy more urgent. Therefore, the development of renewable and clean new energy is of great significance to saving resources, reducing environmental pollution and protecting human health. [0003] Traditional lithium-ion batteries (LIBs) use graphite as the negative electrode, the positive electrode uses oxide materials that can intercalate / extract lithium ions, and the electrolyte is an organic s...

AI Technical Summary

Problems solved by technology

In terms of lithium metal, a common method, such as a method reported in Chinese patent CN103384000A, is to inject lithium metal into a 3D skeleton structure through high-temperature melting to improve the stability of lithium negative electrodes. Although this method has a certain inhibitory effect on the growth of lithium dendrites, the This method will increase the weight of the battery to a large extent, reduce the energy density of the negative electrode, and the preparation process is cumbersome, which is not conducive to commercial production

Separator coating modification can redistribute the diffusion path of lithium ions to a certain extent and achieve the purpose of inhibiting the growth of lithium dendrites (Adv.Energy Mater., DOI: 10.1002 / aenm.201802430), but due to the The source has not been effectively modified, and the modified layer of the separator is easy to redistribute in the electrochemical cycle, resulting in the insufficient density of the modified layer of the separator, exposing the unmodified layer, and the risk of dendrite growth will reappear (Nat.Commun.,2014, 5,5193)

The modification of the electrolyte is considered to be the most potential method to inhibit the growth of lithium dendrites (Adv.Mater., 2017, 1700007). For example, Chinese patent CN 107275671 A reports a method by adding fluoride nanoparticles to the electrolyte, The purpose of inhibiting the growth of lithium dendrites is achieved through the film-forming characteristics of fluoride nanoparticles on the surface of the negative electrode, but this type of additive will gradually become invalid as the cycle increases, and the protective film formed by this type of additive The conductivity of lithium ions is low, which is not conducive to high-current charge and discharge (such as greater than 3mA / cm 2 )

Images