Titanium Oxide Anode Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries using laminate films with aluminum containers face issues due to volume expansion and shrinkage of electrodes during charge and discharge, leading to performance degradation, and require increased series connections to achieve comparable voltage with traditional lithium-ion batteries.
Innovation Solution
A titanium-containing oxide active material represented by the formula Li(2+w)Na(2−x)M1(x/2)Ti(6−y)M2zO14, where M1 is Sr, Ba, or Pb, and M2 is selected from metallic elements excluding Ti and P, is used, allowing for stable lithium insertion and extraction reactions at lower potentials and gentle potential changes over a wide state-of-charge range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If lithium titanate is used as negative electrode active material, then volume stability and thickness consistency are improved, but battery voltage decreases to approximately 2.5V
Solution Approach 1:
The patent modifies the chemical composition parameters of lithium titanate by introducing substitutions at titanium sites (with elements like Nb, Ta, Mo, W, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Hf) and oxygen site substitutions (with F, Cl, Br, I). These parameter changes alter the electrochemical properties to achieve higher operating voltages (3.0V or higher vs. Li/Li+) while preserving the volume stability characteristics of the spinel structure.
Solution Approach 2:
The patent creates composite materials by combining lithium titanate with other compounds or structures, including surface-modified lithium titanate, core-shell structures, and composites with conductive materials. These composite approaches enhance both the voltage output and the overall performance while maintaining the structural stability benefits.
2Power
If series-connecting number is increased to achieve 3.9V battery voltage, then voltage requirement is met, but device complexity and manufacturing difficulty increase
Solution Approach 1:
By changing the electrochemical parameters of the negative electrode material through compositional modifications and surface treatments, the patent enables single-cell batteries to achieve 3.9V or higher operating voltages. This eliminates the need for series connections of multiple lower-voltage cells, thereby reducing device complexity and manufacturing difficulty.
3Power
If carbon negative electrode is used, then high battery voltage of 3.9V is achieved, but volume expansion and shrinkage cause performance degradation
Solution Approach 1:
The patent combines the advantages of different materials by creating composite structures where lithium titanate-based materials (with their volume stability) are integrated with compounds that enable high voltage operation. Surface modifications and composite approaches allow achieving 3.9V or higher while preventing the performance degradation associated with volume changes.
Solution Approach 2:
The patent applies surface modifications and coatings to specific regions of the negative electrode particles, creating local quality variations that enable high voltage operation at the surface while maintaining the stable bulk structure. This local optimization allows the material to achieve both high voltage and performance stability.
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 active material enables nonaqueous electrolyte batteries with improved input-output characteristics, high voltage, and excellent cycle life, reducing the need for increased series connections and enhancing energy density.
Implementation Method 1
The active material includes a titanium-containing oxide... allowing for stable lithium insertion and extraction reactions at lower potentials
Data Source
AI summary
According to one embodiment, there is provided an active material. The active material includes a titanium-containing oxide. The titanium-containing oxide is represented by a general formula of Li(2+w)Na(2−x)M1(x/2)Ti(6−y)M2zO14. In the general formula, the subscripts w, x, y and z are within ranges of 0≤w≤6, 0<x<2, 0≤y≤3, and 0≤z≤3, respectively. M1 is at least one metallic element selected from the group consisting of Sr, Ba, and Pb. M2 is at least one element selected from the group consisting of metallic elements M (excluding Ti and M1) and P.