Monoclinic Composite Oxide Anode for High-Rate Lithium-Ion Batteries
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Solution Overview
Problem
Secondary batteries with carbon-based negative electrodes face issues such as rapid charge-discharge leading to metallic lithium dendrite precipitation, heat generation, and internal short circuits, while titanium oxide-based electrodes offer stability but have lower energy density and higher voltage, making them unsuitable for high-energy applications.
Innovation Solution
A composite oxide with a monoclinic layered structure, represented by the formula Li w M1 2-x Ti 8-y M2 z O 17+δ, is used as the active material, where M1 includes alkali ions like Cs, K, or Na, and M2 includes elements like Zr, Sn, V, Nb, Ta, Mo, W, Fe, Co, Mn, and Al, to enhance lithium ion insertion and extraction capabilities, thereby improving energy density and charge-discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbon-based negative electrode material is used, then energy density is high, but rapid charge-discharge causes metallic lithium dendrite precipitation and internal short circuits
Solution Approach 1:
The patent changes the potential parameter of the negative electrode material from carbon-based (low potential) to titanium oxide-based (higher potential around 1.5V vs Li/Li+), which fundamentally alters the electrochemical behavior to prevent lithium dendrite formation while maintaining operational safety during rapid charge-discharge cycles
Solution Approach 2:
The patent employs composite oxide materials containing titanium oxide combined with other metal oxides (such as vanadium oxide, niobium oxide, or tungsten oxide) to create a synergistic effect that maintains the high potential characteristic while enhancing capacity and improving charge-discharge rate performance
2Reliability
If titanium oxide-based negative electrode material is used, then rapid charge-discharge performance and stability are improved, but energy density and battery voltage decrease
Solution Approach 1:
The patent uses composite oxide structures where titanium oxide is combined with other metal oxides (V, Nb, Ta, Mo, W) to create materials that maintain the high potential and stability of titanium oxide while the additional components contribute to higher capacity, thereby improving energy density
Solution Approach 2:
The patent modifies specific regions of the titanium oxide structure by incorporating other metal elements at specific sites within the oxide lattice, creating local variations in electronic structure and electrochemical properties that enhance both capacity and charge-discharge rate while maintaining overall structural stability
3Productivity
If titanium oxide-based negative electrode material is used, then charge-discharge rate performance is improved, but battery voltage becomes lower than conventional carbon-based batteries
Solution Approach 1:
The patent combines titanium oxide with other metal oxides that have complementary electrochemical properties, where the composite structure enables faster lithium ion transport (improving charge-discharge rate) while the synergistic effects maintain higher operating voltage compared to pure titanium oxide
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 composite oxide achieves a higher battery voltage and charge-discharge capacity, enabling secondary batteries with improved energy density and rapid charge-discharge rates, while maintaining stability and safety.
Implementation Method 1
a composite oxide with a monoclinic layered structure... to enhance lithium ion insertion and extraction capabilities
Data Source
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AI summary
According to one approach, an active material including a composite oxide is provided. The composite oxide has a monoclinic crystal structure and is represented by the general formula LiwM12-xTi8-yM2zO17+δ, wherein: M1 is at least one selected from the group consisting of Cs, K, and Na; M2 is at least one selected from the group consisting of Zr, Sn, V, Nb, Ta, Mo, W, Fe, Co, Mn, and Al; 0 ≤ w ≤ 10; 0 < x < 2; 0 < y < 8; 0 < z < 8; and -0.5 ≤ δ ≤ 0.5.