Hybrid Battery Anode Analysis Using XRD d-Spacing Inflection Points
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Solution Overview
Problem
Current secondary batteries with carbon-based hybrid negative electrodes face challenges in analyzing and diagnosing degradation during lithiation and delithiation behaviors, making it difficult to determine the cause of capacity reduction between carbon-based and non-carbon based materials.
Innovation Solution
A quantitative analysis method using X-ray diffractometry to measure lattice d-spacing changes during charge/discharge, allowing for the quantification of capacity contributions from carbon-based and non-carbon based materials by identifying inflection points in the discharge capacity graph, and determining degradation causes by analyzing changes in inflection point locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a hybrid negative electrode including both carbon-based and non-carbon based materials is used to increase energy density, then the capacity of the secondary battery is improved, but it becomes difficult to separately analyze and diagnose the degradation behavior of each material component
Solution Approach 1:
The patent segments the overlapping XRD patterns of carbon-based and non-carbon based materials by identifying distinct d-spacing ranges for each material type. Carbon-based materials are analyzed in the range of 3.3-3.8 Å while non-carbon based materials are analyzed in the range of 2.0-3.0 Å, allowing separate quantification of each component's capacity contribution and degradation behavior in the hybrid electrode.
Solution Approach 2:
The patent uses X-ray diffraction (XRD) as an intermediary technique to indirectly measure and differentiate the lithiation/delithiation behaviors of different materials. By detecting characteristic d-spacing changes of each material type through XRD patterns, the method enables separate analysis of capacity contributions without physically separating the materials in the hybrid electrode.
2Reliability
If XRD measurement is performed during charge/discharge to monitor d-spacing changes, then the lithiation/delithiation behavior can be tracked, but the overlapping patterns of different materials make it difficult to distinguish their individual contributions
Solution Approach 1:
The patent applies local quality analysis by examining specific local regions of the XRD pattern corresponding to different d-spacing ranges. Carbon-based materials exhibit characteristic d-spacing changes in the 3.3-3.8 Å range, while non-carbon based materials show changes in the 2.0-3.0 Å range. By focusing analysis on these specific local regions, the method distinguishes individual material contributions despite overall pattern overlap.
3Quantity of substance
If silicon-based materials are used to achieve high theoretical capacity, then the energy density is improved, but volume expansion and cracking occur during alloying with lithium
Solution Approach 1:
The patent analyzes hybrid negative electrodes that combine silicon-based materials with carbon-based materials to create a composite structure. The carbon-based component provides structural stability and buffers the volume expansion of silicon during lithiation, while the silicon component contributes high theoretical capacity. The XRD method quantifies the capacity contribution of each component to evaluate the performance of this composite material system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables non-destructive analysis of capacity contributions and degradation causes in carbon-based hybrid negative electrodes, improving the understanding and performance of secondary batteries by separating the behaviors of carbon-based and non-carbon based materials.
Implementation Method 1
measuring a lattice d-spacing of the carbon based negative electrode active material in the carbon based hybrid negative electrode during charging/discharging of the secondary battery using an X-ray diffractometer
Data Source
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AI summary
Disclosed is a quantitative analysis method of a carbon based hybrid negative electrode comprising preparing a secondary battery comprising a carbon based hybrid negative electrode comprising a carbon based negative electrode active material and a non-carbon based negative electrode active material; measuring a lattice d-spacing of the carbon based negative electrode active material in the carbon based hybrid negative electrode during charging/discharging of the secondary battery using an X-ray diffractometer and plotting a graph of a change in lattice d-spacing value as a function of charge/discharge capacity (X axis); and quantifying capacity contribution of the carbon based negative electrode active material and the non-carbon based negative electrode active material in the total discharge capacity of the secondary battery by detecting an inflection point of the slope of the graph during discharging in the plotted graph.