Monoclinic Beta Titanium Oxide Crystallite Control for Battery Capacity
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Solution Overview
Problem
The practical electrode capacity of monoclinic β-type titanium oxide (TiO2(B)) in non-aqueous electrolyte batteries is significantly lower than its theoretical capacity due to low lithium ion diffusibility, limiting the effective insertion and desorption of lithium ions.
Innovation Solution
The use of monoclinic β-type titanium composite oxide with specific crystallite diameters calculated by wide-angle X-ray diffraction, where the first diameter (X) is larger than the second diameter (Y), enhancing lithium ion diffusion through the (020) surface, thereby improving the battery's capacity and large current characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If monoclinic β-type titanium oxide (TiO2(B)) is used as active material, then theoretical capacity is high (335 mAh/g), but practical electrode capacity is low (170-200 mAh/g) due to low lithium ion diffusibility
Solution Approach 1:
The patent segments the crystallite structure by controlling its diameter to be 10 nm or less, dividing the material into ultra-fine particles that reduce diffusion path lengths and improve lithium ion mobility while maintaining high capacity
Solution Approach 2:
The patent changes the physical parameter of crystallite diameter to 10 nm or less, which fundamentally alters the diffusion characteristics by reducing the distance lithium ions must travel through the solid structure, thereby resolving the contradiction between capacity and diffusibility
2Speed
If crystallite diameter is reduced to improve lithium ion diffusion, then large current characteristics improve, but manufacturing precision and structural control become more difficult
Solution Approach 1:
The patent specifies a precise parameter range (crystallite diameter ≤ 10 nm) that balances diffusion performance with manufacturability, providing a clear target for production while ensuring adequate lithium ion mobility
Solution Approach 2:
The patent uses composite oxide materials with specific crystal structures that naturally form the required ultra-fine crystallite structure, combining multiple material properties to achieve both small size and structural 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 approach increases the effective insertion and desorption of lithium ions, resulting in higher capacity and improved large current characteristics for non-aqueous electrolyte batteries, as the unit lattice is preferentially arranged in the vector direction of the (020) surface, facilitating faster lithium ion diffusion.
Implementation Method 1
the diffusibility of Li ions in a solid is low
Implementation Method 2
a first diameter of the crystallite calculated from a peak present at an angle 2θ of 48 to 49° and a second diameter of the crystallite calculated from a peak present at an angle 2θ of 24 to 26°, by the wide-angle X-ray diffraction method
Data Source
AI summary
According to one embodiment, an active material for batteries includes monoclinic β-type titanium composite oxide having a crystallite, wherein the monoclinic β-type titanium composite oxide has a first diameter of the crystallite calculated from a peak present at an angle 2θ of 48 to 49° and a second diameter of the crystallite calculated from a peak present at an angle 2θ of 24 to 26°, by the wide-angle X-ray diffraction method using an X-ray source CuKα ray, the first diameter of the crystallite is defined as X and the second diameter of the crystallite is defined as Y, X is larger than Y.