Monoclinic Niobium-Titanium Composite Oxide for Battery Anodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonaqueous electrolyte batteries face challenges with rapid charge-and-discharge performance and energy density due to dendrite formation and low capacity density when using carbon-based materials, and titanium oxide-based batteries have limitations in energy density and capacity.
Innovation Solution
Development of a monoclinic niobium-titanium composite oxide active material with specific crystal structure and composition, including elements like Mo, V, and W, to enhance lithium ion insertion and extraction capabilities, improving energy density and charge-discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbonaceous material is used as negative electrode active material, then capacity per weight is high, but dendrite precipitation occurs during rapid charge-and-discharge
Solution Approach 1:
A lithium ion conductive coating layer is applied to the surface of the lithium metal negative electrode. This coating acts as an intermediary that facilitates lithium ion transport while preventing direct contact between lithium metal and the electrolyte, thereby eliminating dendrite precipitation while maintaining high capacity.
Solution Approach 2:
The invention changes the surface properties of the lithium metal electrode by applying a coating layer with specific lithium ion conductivity. This parameter change allows the electrode to function safely during rapid charge-and-discharge cycles by controlling lithium ion transport at the electrode surface.
2Productivity
If titanium oxide is used as negative electrode active material, then rapid charge-and-discharge performance is good, but energy density is low
Solution Approach 1:
Instead of using titanium oxide as the main negative electrode material, the invention inverts the approach by using lithium metal as the negative electrode with a protective coating. This inversion allows achieving both high energy density and good charge-discharge performance by leveraging lithium metal's high capacity while using the coating to enable rapid ion transport.
3Quantity of substance
If lithium metal negative electrode is used, then energy density is high, but dendrite formation and safety issues occur
Solution Approach 1:
A lithium ion conductive coating layer is introduced as an intermediary between the lithium metal and the electrolyte. This coating layer has high lithium ion conductivity but low electronic conductivity, which prevents dendrite formation and improves safety while allowing lithium metal to maintain its high energy density advantage.
Solution Approach 2:
The surface conductivity parameters of the lithium metal electrode are modified by applying the coating layer. The coating provides high lithium ion conductivity while maintaining low electronic conductivity, fundamentally changing the electrode's interface properties to eliminate harmful effects.
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 monoclinic niobium-titanium composite oxide active material achieves high capacity and rapid charge-discharge performance while maintaining structural stability, enhancing the energy density and cycle characteristics of nonaqueous electrolyte batteries.
Implementation Method 1
enhance lithium ion insertion and extraction capabilities
Implementation Method 2
The potential of the electrode using titanium oxide is due to the redox reaction between Ti3+ and Ti4+ when lithium is electrochemically inserted and extracted
Data Source
AI summary
In general, according to one embodiment, there is provided an active material. The active material contains active material primary particles of a monoclinic niobium-titanium composite oxide. The monoclinic niobium-titanium composite oxide contains at least one element selected from the group consisting of Mo, V, and W. A content of the at least one element in the monoclinic niobium-titanium composite oxide is within a range of 0.01 atm % or more and 2 atm % or less. Each of the active material primary particles has an aspect ratio within a range of 1 or more and less than 4 of a primary particle and a crystallite size within a range of 5 nm or more and 90 nm or less.