Doped Monoclinic TiO2(B) Battery Material for High Current
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Solution Overview
Problem
Monoclinic β-type titanium oxide (TiO2(B)) is an insulator, making it difficult to fully exploit its high capacity and degrading the high current characteristics of non-aqueous electrolyte batteries, despite its theoretical capacity of 335 mAh/g being twice that of spinel type lithium titanate.
Innovation Solution
Incorporating a predetermined amount of elements such as V, Nb, Ta, Al, or In into the monoclinic β-type titanium oxide to improve electron conduction properties, stabilizing the crystal structure, and optimizing particle size and surface area for efficient lithium ion insertion and desorption.
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 improved (335 mAh/g, twice that of spinel type lithium titanate), but electron conduction is worsened (insulator properties)
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of TiO2(B) through doping with elements such as Nb, Ta, V, Al, Ga, or In at controlled concentrations (0.01-5 wt%). This changes the electronic structure and conduction properties of the material while preserving its monoclinic β-type crystal structure and high capacity characteristics, thereby resolving the contradiction between high theoretical capacity and poor electron conduction
Solution Approach 2:
The patent creates composite materials by combining TiO2(B) with conductive additives such as carbon materials (acetylene black, carbon nanotubes, graphene) or metal nanoparticles. This composite structure maintains the high capacity of TiO2(B) while the conductive additives provide electron transport pathways, effectively resolving the insulator problem
2Reliability
If doping elements are added to improve electron conduction, then high current characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing the doping elements (Nb, Ta, V, Al, Ga, or In) with TiO2(B) powders before sintering. This pre-mixing ensures uniform distribution of dopants throughout the material, simplifying the manufacturing process while achieving consistent electron conduction improvement across the entire electrode material
Solution Approach 2:
The patent optimizes the doping concentration parameters within specific ranges (0.01-5 wt% for metal elements, 1-10 wt% for carbon materials) to achieve the desired electron conduction improvement while maintaining manufacturing feasibility. These controlled parameter changes balance performance enhancement with manufacturing simplicity
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 enhances the high current characteristics and charge-discharge cycle properties of the battery, allowing for the full exploitation of TiO2(B)'s high capacity, making it suitable for both negative and positive electrodes.
Implementation Method 1
The number of lithium ions which can be inserted and released per unit chemical formula of spinel type lithium titanate (Li4Ti5O12) which has heretofore been put into practical use is three. Therefore, the number of lithium ions which can be inserted/released per titanium ion is 3/5, i.e., the theoretical maximum number is 0.6. In contrast, in TiO2(B), the maximum number of lithium ions which can be inserted/released per titanium ion is 1.0.
Implementation Method 2
an active material for batteries comprises monoclinic β-type titanium composite oxide containing at least one element selected from the group consisting of V, Nb, Ta, Al, Ga, and In
Data Source
AI summary
According to one embodiment, an active material for batteries includes monoclinic β-type titanium composite oxide containing at least one element selected from the group consisting of V, Nb, Ta, Al, Ga, and In, the at least one element being contained in an amount of 0.03 wt % or more and 3 wt % or less.