Niobium-Titanium Negative Electrode Coating for Battery Life
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Solution Overview
Problem
Secondary batteries used in hybrid electric vehicles experience rapid side reactions at the negative electrode during shallow charge-discharge cycles, leading to an imbalance in the operation window between the positive and negative electrodes, which results in premature deterioration of the positive electrode.
Innovation Solution
A secondary battery design featuring a negative electrode with niobium-titanium composite oxide, where fluorine atoms are present on the surface, with a specific abundance ratio of fluorine, titanium, and niobium atoms, forming a fluorine-containing coating film that aligns the side reaction rates with the positive electrode, thereby reducing the shift in the operation window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If shallow charge-discharge cycles are used for high input-output performance, then power delivery is improved, but side reactions at the negative electrode accelerate causing operation window imbalance and positive electrode deterioration
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the negative electrode material. Specifically, it adjusts the ratio of Ti to Nb atoms and controls the fluorine content (represented by parameter x in Ti1-xNbxO2-yFy) to optimize the material properties. This parameter optimization suppresses side reactions while maintaining high power performance, resolving the contradiction between power delivery and battery life.
Solution Approach 2:
The patent employs composite materials by creating a niobium-titanium composite oxide structure where Ti and Nb atoms are combined in specific ratios. This composite structure leverages the complementary properties of both elements: Ti provides structural stability while Nb enhances electrochemical performance. The composite material approach enables simultaneous achievement of high power output and extended cycle life.
2Ease of manufacture
If the negative electrode uses conventional materials, then manufacturing is simpler, but side reactions advance faster than positive electrode reactions causing operation window shift
Solution Approach 1:
The patent modifies the compositional parameters of the negative electrode material by controlling the Ti:Nb ratio and fluorine content (parameter x and y in Ti1-xNbxO2-yFy). These parameter adjustments optimize the electrochemical stability and reaction balance between electrodes, preventing operation window shift while maintaining manufacturability through conventional ceramic processing techniques.
Solution Approach 2:
The patent applies local quality by creating a non-stoichiometric composition with controlled deviations from ideal ratios. The parameters x and y allow fine-tuning of local chemical environments within the crystal structure, optimizing surface properties and reaction characteristics at specific sites while maintaining overall material stability and manufacturability.
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
This configuration effectively suppresses side reactions at the negative electrode, maintaining a stable operation window and enhancing the battery's life performance, even under high output conditions.
Implementation Method 1
the niobium-titanium composite oxide has fluorine atoms on at least part of a surface the niobium-titanium composite oxide
Implementation Method 2
This configuration effectively suppresses side reactions at the negative electrode, maintaining a stable operation window and enhancing the battery's life performance
Data Source
AI summary
According to one embodiment, provided is a secondary battery including a positive electrode, a negative electrode, and an electrolyte. The negative electrode includes a niobium-titanium composite oxide having fluorine atoms on at least part of a surface the niobium-titanium composite oxide. An abundance ratio AF of fluorine atoms, an abundance ratio ATi of titanium atoms, and an abundance ratio ANb of niobium atoms on a surface of the negative electrode according to X-ray photoelectron spectroscopy satisfy a relationship of 3.5≤AF/(ATi+ANb)≤50.