Evaluation method of interface between lithium ion battery anodes and electrolytes

Abstract

The invention provides an evaluation method of an interface between lithium ion battery anodes and electrolytes. The method comprises the steps that a certain batch of anode plates with one face coated are selected, a certain electrolyte is adopted, and the anode plates are assembled into symmetric batteries; after standing is conducted for a period of time, a constant current is applied to the symmetric batteries, and circulating performance testing is conducted; a changing curve of polarizing voltage of the symmetric battery with testing time is drawn; the stability of an SEI membrane formed on the interface of the batch of the anode plates and the electrolyte and the compatibility of active materials of the batch of the anode plates and the electrolyte are analyzed and judged; the same batch of the anode plates with the one side coated are selected, a different electrolyte is adopted, the anode plates are assembled into symmetric batteries, and the steps are repeatedly conducted. According to the evaluation method of the interface between the lithium ion battery anodes and the electrolytes, not only can the stability of the SEI membrane formed on the interface of the battery anodes and the electrolytes be effectively evaluated, but also the compatibility of the anode active materials and the electrolytes can be effectively evaluated, and meanwhile shortening of the screening time of the electrolytes is facilitated.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery detection, in particular to an evaluation method for the interface between a negative electrode of a lithium-ion battery and an electrolyte. Background technique [0002] During the first charging and discharging process of the liquid lithium-ion battery, the electrode material and the electrolyte react at the solid / liquid interface to form a passivation layer covering the surface of the electrode material. This passivation layer is an interface layer, which has the characteristics of a solid electrolyte. It is an electronic insulator but an excellent conductor of Li+. Li+ can be freely inserted and extracted through the passivation layer, so this passivation film is called "Solid electrolyte interface film" (solid electrolyte interface), referred to as SEI film. [0003] The formation of SEI film has a crucial impact on the performance of electrode materials. On the one hand, the ...

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Problems solved by technology

[0004] At present, there are many studies on the formation mechanism and composition of the SEI film, but there are few evaluation methods for the stability of the SEI film, and there are few detection methods for the compatibility between the negative electrode active material and the electrolyte. A new method for effectively evaluating the interface between the anode and the electrolyte of lithium-ion batteries has strong practical significance

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