Tubular Lithium Composite Cathode for SEI Lithium Loss
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Solution Overview
Problem
The consumption of lithium ions during the formation of a solid electrolyte interface (SEI) film on the negative electrode surface in battery cells reduces the cell capacity, necessitating a solution to supplement lithium ions and improve capacity.
Innovation Solution
A composite material comprising a lithium-containing compound, a catalyst, and a carbon material with a hollow tubular structure, where the lithium-containing compound and catalyst are arranged within the tubular structure, facilitating lithium ion production and decomposition at a lower voltage, supported by a transition metal oxide, carbide, or nitride catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte interface (SEI) film is formed on the negative electrode surface, then the battery structure is stabilized, but lithium ions are consumed and cell capacity is reduced
Solution Approach 1:
The patent introduces a lithium-containing compound into the positive electrode material before battery operation. This compound serves as a preliminary lithium source that can supplement lithium ions to the negative electrode during subsequent charging cycles, compensating for the lithium ions consumed during SEI film formation and thereby maintaining cell capacity
Solution Approach 2:
The patent changes the chemical composition parameter of the positive electrode by incorporating a lithium-containing compound with specific chemical formula Li2CxOy (where 1≤x≤4 and 3≤y≤6). This parameter change enables the positive electrode to release lithium ions under specific conditions, balancing the lithium ion consumption in the negative electrode
2Quantity of substance
If a lithium-containing compound is added to supplement lithium ions, then cell capacity is improved, but the compound may decompose at high voltage causing structural damage
Solution Approach 1:
The patent introduces a transition metal oxide catalyst as an intermediary substance that facilitates the decomposition of the lithium-containing compound at lower voltages. This catalyst acts as a mediator between the lithium-containing compound and the electrode structure, enabling lithium ion release while preventing direct high-voltage damage to the electrode structure
Solution Approach 2:
The patent changes the decomposition voltage parameter of the lithium-containing compound by introducing a catalyst. The transition metal oxide catalyst lowers the decomposition voltage from high values that would damage the electrode structure to lower values that are safe for the electrode while still enabling lithium ion supplementation
3Reliability
If a catalyst is used to lower decomposition voltage, then lithium ion supplementation occurs at safer voltages, but the catalyst may escape from the electrode structure
Solution Approach 1:
The patent embeds the transition metal oxide catalyst particles within the hollow tubular structure of the carbon material. This nested arrangement allows the catalyst to be contained securely within the carbon tube, preventing catalyst escape while maintaining its catalytic function for lowering the decomposition voltage of the lithium-containing compound
Solution Approach 2:
The patent creates a composite material system consisting of carbon material with hollow tubular structure containing transition metal oxide catalyst particles, which in turn are surrounded by or in contact with the lithium-containing compound. This composite structure integrates multiple functions: carbon provides structural support and containment, transition metal oxide provides catalysis, and the lithium-containing compound provides lithium ion source
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 material enhances lithium ion supplementation, improves battery capacity, maintains conductivity, and reduces structural damage to the positive electrode, thereby increasing the cell's capacity and stability.
Implementation Method 1
the lithium-containing compound can decompose to produce lithium ions and gas, to supplement lithium ions to the battery
Implementation Method 2
The catalyst may catalyze decomposition of the lithium-containing compound
Data Source
AI summary
This application discloses a composite material and a preparation method therefor, a positive electrode plate, a cell, a battery, and an electric device, and belongs to the field of battery technologies. A composite material includes a lithium-containing compound, a catalyst, and a carbon material. The carbon material has a hollow tubular structure, and the lithium-containing compound and the catalyst are arranged in the tubular structure. The lithium-containing compound includes lithium, carbon, and oxygen. The catalyst includes at least one of a transition metal oxide, a transition metal carbide, or a transition metal nitride. Technical solutions of embodiments of this application can improve a capacity of a cell.