Method for exploring influence of interface potential on lithium ion transportation by using electronic holography

Abstract

The invention provides a method for exploring the influence of interface potential on lithium ion transportation by using an electronic holographic technology, the microscopic transportation process of lithium ions in a solid electrode is a direct factor for determining the macroscopic electrochemical behavior of a lithium ion battery, and currently common methods such as neutron diffraction and nuclear magnetic resonance are limited by the influence of resolution. According to the method disclosed by the invention, the resolution ratio is improved to an atomic level, and the potential distribution of the polycrystalline grain boundary of the positive electrode material of the lithium ion battery is accurately measured by combining an objective lens spherical aberration correction transmission electron microscope with an electronic holographic technology; the method sequentially comprises the steps of obtaining an electron hologram, extracting a separated phase diagram and an amplitude diagram through digital reconstruction, and obtaining an image related to phase shift and potential distribution through further data processing, so that statistical results of interface potential difference and potential barrier distribution are obtained, and the dynamics problem of a lithium ion transmission mechanism is further revealed. And the method has important research significance on construction of a lithium ion battery structure-performance relationship.

Description

technical field [0001] The invention relates to the field of microscopic characterization of the interface potential of polycrystalline positive electrode materials of lithium ion batteries, and specifically discloses a method for exploring the influence of interface potential on lithium ion transport by using electron holography. Background technique [0002] The microscopic transport process of lithium ions in solid electrodes is a direct factor that determines the macroscopic electrochemical behavior of lithium-ion batteries. At present, the characterization methods for lithium ion transport mainly include neutron diffraction (XD), nuclear magnetic resonance (NMR), secondary ion mass spectrometry (SIMS) and galvanostatic intermittent titration technology (GITT), etc. Although these methods are used in the determination of Li+ diffusion coefficient , Li+ occupancy, and Li+ concentration change monitoring, but they are not sensitive to the microscopic local structure of the...

AI Technical Summary

Problems solved by technology

Now it has been widely used in the measurement of sample thickness, the determination of the average internal potential, and the observation of the space charge layer and potential distribution at the interface, etc., and has shown important application prospects in the field of solid-state batteries with high conductive interfaces based on nano-ionics. However, there is still a lack of detailed method explanations on how to establish the relationship between the interfacial potential distribution and the lithium ion transport performance.

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