Electrochemical Optics Spectroscopic Cell for In Situ Research

Abstract

The invention discloses an electrochemical-optical combined in-situ study spectral cell. The electrochemical-optical combined in-situ study spectral cell comprises a cell body (5), a semi-cylindrical crystal light transmission window plate (1), a sample platform (8) and a reference electrode (9), wherein a layer of active substance film with the thickness at nanometer level is coated on the bottom plane of the semi-cylindrical crystal light transmission window plate (1) to be used as the a working electrode (12); a conducting line is led from the working electrode (12); the sample platform (8) is placed at the bottom part of the cell body (5) opposite to the working electrode (12); the reference electrode (9) is fixed relative to the working electrode (12) on the sample platform (8) by a conductive adhesive; and another conducting line is led from the reference electrode (9). By adopting the electrochemical-optical combined in-situ study spectral cell, spectral signals can be prevented from being absorbed by the solution; the real electrochemical reaction can be simulated; the electrochemical-optical combined in-situ spectral cell can be used in coupling with a spectrometer; the incident ray can be continuously adjusted from a smaller angle (15 degrees); and liquid in the cell body can flow so as to be exchanged.

Description

technical field [0001] The invention relates to a spectroscopic cell, in particular to a spectroscopic cell for in-situ detection of electrode solid-liquid interface molecular behavior during an electrochemical reaction process in combination with electrochemistry and optics. Background technique [0002] During the first charge and discharge process of lithium-ion batteries, a passivation film, called SEI film, will be formed on the surface of the negative electrode. The SEI film can allow lithium ions to pass through, but not electrons, and can prevent further embedding of solvent molecules on the electrode surface, thereby improving the cycle performance, rate performance, reversible capacity and safety performance of lithium-ion batteries. [0003] Since the SEI film plays a very important role in lithium-ion batteries, it has attracted more and more attention. Although people have done a lot of research on SEI membranes, most of the research is off-line, and off-line r...

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Problems solved by technology

[0004] 1. Due to the sensitivity of the composition and structure of the SEI film to the environment, it cannot accurately reflect the in-situ state of the SEI film during the electrode reaction process or even after the end

[0005] 2. Even if it can reflect the final composition of the SEI film, it cannot reflect the specific formation process and dynamic evolution mechanism of the SEI film at the electrode interface during the electrode process

[0006] 3. It is impossible to obtain the microscopic information of the interface on the solution side during the electrode reaction process, such as the change rule and molecular behavior of the electric double layer structure, and its relationship with the formation and evolution of the SEI film

[0007] 4. Unable to analyze the interaction mechanism between the microscopic behavior of the electrode interface and the kinetic and thermodynamic macroscopic parameters of the electrode process

[0009] The Institute of Chemistry, Chinese Academy of Sciences proposed an in-situ thin-layer spectroelectrochemical reaction cell, which uses a semi-cylindrical calcium fluoride crystal as the window, which can adapt to multiple incident light angles. The distance between the working electrode and the working electrode is reduced to about 8 microns, which greatly reduces the absorption of the spectral signal by the solution, and can effectively perform in-situ spectral characterization of the electrochemical system (CN102539328A), but the solution will still affect the spectral signal. have a certain impact

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