Na2Ti3O7 Negative Electrode with Network-Forming Oxide
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Solution Overview
Problem
The layered sodium titanium oxide Na2Ti3O7 negative electrode active material exhibits a low discharge capacity retention rate, limiting its cycle performance in electricity storage devices.
Innovation Solution
A negative electrode active material comprising TiO2, Na2O, and a network-forming oxide, such as B2O3, with a monoclinic crystal structure and amorphous phase, is developed, along with a production method involving melting and firing to create crystallized glass particles coated with conductive carbon, optimizing the composition and structure for improved ion conductivity and discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbon materials are used as negative electrode active material, then good cycle performance is achieved, but battery capacity is limited
Solution Approach 1:
The patent develops composite materials combining TiO2 with Na2O and network-forming oxides to create a new class of negative electrode active materials. These composites achieve both high battery capacity (exceeding conventional carbon materials) and good cycle performance, resolving the contradiction between capacity and reliability.
Solution Approach 2:
The patent changes the compositional parameters by incorporating specific ratios of TiO2, Na2O, and network-forming oxides. This parameter optimization enables the material to achieve higher battery capacity while maintaining excellent cycle performance, overcoming the limitations of conventional carbon materials.
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 solution provides a negative electrode active material with a high discharge capacity retention rate and enhanced rapid charge-discharge performance, effectively addressing the low cycle performance of Na2Ti3O7, as demonstrated by improved discharge capacities and retention rates in both sodium ion and lithium ion secondary batteries.
Implementation Method 1
melting the batch to obtain molten glass
Implementation Method 2
cooling the molten glass to obtain a melt-solidified body
Implementation Method 3
firing the melt-solidified body powder at from 500° C. to 1000° C. to obtain crystallized glass powder
Implementation Method 4
firing the melt-solidified body powder at from 500° C. to 1000° C. to obtain crystallized glass powder
Data Source
AI summary
A negative electrode active material for an electricity storage device of the present invention includes TiO2, Na2O, and a network-forming oxide.