Monoclinic Composite Oxide Anode for High-Energy Fast-Charging Batteries
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Solution Overview
Problem
Existing lithium-ion secondary batteries face challenges in achieving high energy density and rapid charge-discharge performance due to the use of carbon-based negative electrodes, which can lead to metallic lithium dendrite formation and reduced capacity, and alternative materials like Li4Ti5O12 offer lower theoretical capacity and energy density.
Innovation Solution
A composite oxide with a monoclinic crystal structure, represented by Li x Nb16-y-zMzW5+yO55-u, is synthesized under highly airtight conditions to suppress tungsten volatilization, enhancing capacity and conductivity, and is used in electrodes to create high-capacity secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon-based negative electrode is used, then battery cost and ease of manufacture are improved, but energy density and theoretical capacity deteriorate
Solution Approach 1:
The patent uses composite oxide materials (spinel Li4Ti5O12 combined with other metal oxides) as negative electrode active materials to achieve high energy density while maintaining manufacturability. The composite structure allows optimization of both capacity and operational characteristics.
Solution Approach 2:
The patent changes the operating potential parameter of the negative electrode from typical carbon-based values to higher potentials (1.55V average for spinel, with modifications to achieve near 1V operation). This parameter change enables higher energy density while avoiding lithium dendrite formation.
2Power
If rapid charge-discharge is performed, then power output is improved, but lithium dendrite precipitation and safety issues worsen
Solution Approach 1:
The patent changes the operating potential parameter to 1.55V average (spinel) or near 1V (modified compositions), which is significantly higher than carbon-based electrodes. This potential parameter change enables rapid charge-discharge at high power while preventing lithium dendrite precipitation that causes safety issues.
Solution Approach 2:
The patent uses spinel Li4Ti5O12 and modified composite oxides as negative electrode materials that can withstand rapid charge-discharge cycles without degradation. These materials provide short-term high power output capability while maintaining long-term safety and reliability.
3Power
If spinel Li4Ti5O12 is used to increase operating potential, then rapid charge-discharge performance is improved, but energy density deteriorates due to low capacity
Solution Approach 1:
The patent combines spinel Li4Ti5O12 with other metal oxides to create composite negative electrode materials. This composite approach maintains the high power performance and 1.55V operating potential of spinel while adding capacity contributions from the other materials, achieving both rapid charge-discharge capability and higher energy density.
Solution Approach 2:
The patent merges the advantages of spinel Li4Ti5O12 (high operating potential, rapid charge-discharge performance) with other metal oxide materials (additional capacity) to create a composite negative electrode that achieves both high power and high capacity, resolving the contradiction between rapid charge-discharge performance and energy density.
4Quantity of substance
If monoclinic niobium-titanium composite oxide is used to achieve high capacity near 1V, then energy density is improved, but manufacturing complexity increases due to synthesis conditions
Solution Approach 1:
The patent modifies the synthesis parameters (temperature, atmosphere control) to achieve the monoclinic crystal structure of niobium-titanium composite oxide with high capacity near 1V operating potential. By optimizing these parameters, the patent achieves high energy density while managing manufacturing complexity through controlled synthesis conditions.
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 improved reversible capacity and electrical conductivity, resulting in secondary batteries with increased energy density and rapid discharge performance.
Implementation Method 1
optimized particle sizes and specific surface areas for improved lithium ion diffusion
Implementation Method 2
secondary batteries such as a lithium-ion secondary battery or a nonaqueous electrolyte secondary battery
Data Source
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Figure 5
AI summary
According to one approach, provided is an active material including a composite oxide having a monoclinic crystal structure. The composite oxide is represented by a general formula LixNb16-y-zMzW5+yO55-u. Herein, M includes at least one selected from the group consisting of Ta, Ti, Zr, Al, and Fe, and 0 ≤ x ≤ 5, -0.5 ≤ y ≤ 2, 0 ≤ z ≤ 2, and 4 ≤ u ≤ 9.