Na2Ti6O13 Anode Capacity via Dual Na Insertion
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Solution Overview
Problem
Sodium ion batteries using Na2Ti6O13 as anode active material exhibit low initial charge and discharge efficiency, with a reversible capacitance of approximately 27% and 20 mAh/g, limiting their capacity.
Innovation Solution
A sodium ion battery system with a charge control unit that controls electric current and potential to induce a second Na insertion reaction on the lower electric potential side in addition to the first Na insertion reaction in the Na2Ti6O13 crystal phase, enhancing capacity by utilizing the Na2Ti6O13 crystal phase's tunnel structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional charging conditions are used for Na2Ti6O13 anode, then the battery structure is simple and easy to operate, but the reversible capacitance is low (approximately 20 mAh/g) and initial charge-discharge efficiency is low (approximately 27%)
Solution Approach 1:
The patent applies parameter changes by controlling charging conditions (electric potential and current density) to enable a second Na insertion reaction at lower electric potential (0.0-0.1V vs Na/Na+). This changes the electrochemical parameters to achieve higher reversible capacitance (110 mAh/g) while managing the complexity through defined control parameters.
2Reliability
If conventional charging conditions are used for Na2Ti6O13 anode, then the operating procedure is simple, but the initial charge-discharge efficiency is low (approximately 27%)
Solution Approach 1:
The patent improves reliability by changing charging parameters (electric potential control to 0.0-0.1V vs Na/Na+ and current density control) to achieve the second Na insertion reaction, raising initial charge-discharge efficiency from 27% to 70% or higher.
3Quantity of substance
If conventional charging conditions are used for Na2Ti6O13 anode, then the battery system is simple to operate, but the capacity is limited (approximately 20 mAh/g)
Solution Approach 1:
The patent achieves higher battery capacity (110 mAh/g) by changing charging parameters to enable dual Na insertion reactions. The charge control system manages complexity through defined potential and current density parameters while achieving 5.5x capacity improvement.
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
The system achieves higher capacity by facilitating further Na ion insertion, increasing reversible capacitance to approximately 110 mAh/g, surpassing conventional limits.
Implementation Method 1
a second Na insertion reaction on the lower electric potential side in addition to a first Na insertion reaction in the above-mentioned Na2Ti6O13 crystal phase
Data Source
AI summary
The problem of the present invention is to provide a sodium ion battery system capable of intending higher capacity. The present invention solves the above-mentioned problem by providing a sodium ion battery system comprising a sodium ion battery and a charge control unit, wherein the anode active material is an active material having an Na2Ti6O13 crystal phase, and the above-mentioned charge control unit controls electric current and electric potential of the above-mentioned anode active material so as to cause a second Na insertion reaction on the lower electric potential side in addition to a first Na insertion reaction in the above-mentioned Na2Ti6O13 crystal phase.