Solid electrolyte composite layer and lithium ion battery

Abstract

The invention provides a solid electrolyte composite layer and a lithium ion battery. The solid-state electrolyte composite layer comprises a near-positive-electrode-side solid-state electrolyte layer, a middle solid-state electrolyte layer and a near-negative-electrode-side solid-state electrolyte layer which are sequentially arranged in a stacked mode. The middle solid-state electrolyte layer comprises the inorganic ceramic electrolyte, the near-positive-electrode-side solid electrolyte layer comprises near-positive-electrode-side polymer with high oxidation resistance, and the near-negative-electrode-side solid electrolyte layer comprises a near-negative-electrode-side compound stable with metal lithium, so that the solid electrolyte composite layer is high in mechanical strength, and lithium dendrites are prevented from piercing the electrolyte; the requirements of high-voltage resistance of a positive electrode side and stability of a negative electrode side and metal lithium aremet, and meanwhile, the interface wettability of the solid electrolyte composite layer is good. The lithium ion battery comprises the solid electrolyte composite layer, and due to the fact that the solid electrolyte composite layer is high in mechanical strength, excellent in wettability and good in stability with positive and negative electrode interfaces, the lithium ion battery has the advantages of being small in battery internal resistance, good in cycle performance and high in safety.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to a solid electrolyte composite layer and a lithium ion battery. Background technique [0002] In recent years, among various commercial rechargeable and dischargeable chemical energy storage devices, lithium-ion batteries have the characteristics of high energy density and long service life, and have been widely used in mobile phones, notebook computers, electric vehicles and other fields. At present, most of the electrolytes used in lithium-ion batteries are liquid organic electrolytes. Liquid organic electrolytes are volatile, flammable and explosive, which seriously affects the safety of lithium-ion batteries during use. [0003] Solid-state electrolytes have high mechanical strength, excellent density, and the ability to resist the growth of lithium dendrites, and have no volatile, flammable and explosive characteristics of liquid organic electrolytes. Therefore, if solid-st...

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Problems solved by technology

Among them, the inorganic ceramic solid electrolyte has the advantages of good ionic conductivity, negligible electronic conductivity, and wide electrochemical window, but its own large grain boundary resistance and poor physical contact with the positive and negative electrodes ; The organic polymer solid electrolyte has good flexibility and processability, but the ionic conductivity at room temperature is too low, and lithium dendrites are easy to pierce the electrolyte and cause a short circuit in the battery; the inorganic ceramic / polymer composite solid electrolyte is a combination of inorganic ceramic solid electrolyte and polymer The advantages of solid-state electrolytes not only maintain a strong lithium ion transport capacity, but also avoid the potential short circuit caused by lithium dendrites piercing the electrolyte. However, the commonly used composite method is to uniformly mix inorganic ceramic powder and polymer matrix. This composite method is not easy to adjust precisely according to the requirements of high voltage resistance on the positive side and stable compatibility with lithium metal on the negative side.

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