Positive Electrode Core-Shell Lithium Supplement for Uniform Li Distribution
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Solution Overview
Problem
Existing energy storage apparatuses face issues with lithium precipitation and poor lithium supplement effects, leading to reduced cycle life and safety hazards due to non-uniform lithium distribution and excessive lithium addition.
Innovation Solution
The energy storage apparatus incorporates a positive electrode sheet with a lithium-supplement particle design, featuring a lithium-supplement core and outer shell, ensuring a specific ratio and distribution of the outer shell's path length, thickness, and particle size to enhance lithium uniformity and prevent lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If lithium supplement particles are added to improve lithium distribution, then lithium uniformity is improved, but lithium precipitation occurs due to excessive or non-uniform lithium addition
Solution Approach 1:
The lithium supplement particle is segmented into a core-shell structure where the core contains the lithium supplement material and the shell contains the positive electrode active material. This segmentation allows controlled lithium release while preventing direct contact between excessive lithium supplement and the electrolyte, thus avoiding lithium precipitation while maintaining lithium distribution uniformity.
Solution Approach 2:
The lithium supplement particle exhibits local quality differentiation through its core-shell structure. The core region provides lithium supplement function while the shell region provides structural stability and controlled lithium release. This local quality differentiation ensures lithium is supplemented uniformly without causing precipitation in specific areas.
2Reliability
If more lithium supplement material is added to ensure sufficient lithium supply, then lithium supplement effect is improved, but lithium precipitation and safety hazards increase
Solution Approach 1:
The lithium supplement material is pre-encapsulated in the core-shell structure during particle formation, creating a controlled release mechanism. This preliminary action ensures lithium is supplemented at the right rate and amount, preventing both insufficient lithium supply and excessive lithium accumulation that would cause safety hazards.
Solution Approach 2:
The shell acts as an intermediary between the lithium supplement core and the electrolyte. It controls the rate and amount of lithium release, ensuring sufficient lithium supplement effect while preventing direct interaction between excessive lithium supplement material and the electrolyte, thus eliminating safety hazards.
3Loss of substance
If lithium supplement particles with high lithium content are used to reduce lithium consumption, then lithium efficiency is improved, but non-uniform lithium distribution occurs
Solution Approach 1:
The lithium supplement particle utilizes parameter changes through its core-shell structure, where the shell thickness and composition are optimized to control lithium release kinetics. This allows high lithium content in the core to be released uniformly over time, improving lithium efficiency while maintaining distribution uniformity.
Data Source
AI summary
An energy storage apparatus is provided. The apparatus includes an electrode assembly, including a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet includes a current collector and an active material layer. The active material layer includes a first lithium-containing compound and a second lithium-containing compound being a lithium-supplement particle and including a lithium-supplement core and an outer shell. A connection area and a separation area are formed between the lithium-supplement core and the outer shell. The ratio of the path length of the outer shell of the lithium-supplement particle in the connection area to the total circumference of the outer shell within a cross-section of the positive electrode sheet is greater than or equal to 5% and less than or equal to 45%.