Negative Electrode Active Material With Dual-Pore Balance
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Solution Overview
Problem
The challenge lies in achieving a balance between high energy density and high kinetic performance in lithium-ion batteries, as increasing energy density often degrades kinetic performance.
Innovation Solution
A negative electrode active material with specific pore size distribution, comprising mesopores of 2nm to 50nm and macropores of 100nm to 200nm, with a volume ratio of mesopores to macropores (B/A) between 3.0 and 5.0, enhancing liquid absorption capacity and electronic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If energy density is increased, then the battery can store more energy, but kinetic performance deteriorates
Solution Approach 1:
The negative electrode active material is segmented into a dual-pore structure with mesopores (2-50nm) and macropores (100-200nm). This segmentation creates distinct functional zones: mesopores provide high surface area for lithium ion insertion/extraction (improving kinetic performance), while macropores provide buffer space for volume expansion during cycling (maintaining structural integrity and energy density). The specific volume ratio B/A=3.0-5.0 optimizes the balance between these functions.
Solution Approach 2:
Different pore sizes are assigned different local functions within the same material structure. Mesopores (2-50nm) are optimized for lithium ion transport and electrochemical reactions, while macropores (100-200nm) are optimized for mechanical buffering and structural stability. This local differentiation allows each pore type to excel at its specific function while contributing to overall performance.
2Reliability
If mesopore volume is increased, then liquid absorption capacity and electronic conductivity improve, but lithium source consumption during film formation increases
Solution Approach 1:
The invention optimizes the pore size parameter within the specific range of 2-50nm for mesopores and 100-200nm for macropores. This parameter optimization ensures that mesopores are large enough to facilitate lithium ion transport and improve kinetic performance, but not so large that they excessively consume lithium sources during film formation. The macropores provide additional buffer capacity without significantly increasing lithium consumption.
Solution Approach 2:
The negative electrode active material is designed as a composite porous structure combining mesopores and macropores in specific proportions (B/A=3.0-5.0). This composite structure leverages the advantages of both pore types: mesopores provide high surface area for reactions with controlled lithium consumption, while macropores provide mechanical buffering, achieving kinetic performance improvement without excessive lithium source loss.
3Stability of the object's composition
If macropore volume is increased, then interlayer structure expansion is buffered, but kinetic performance decreases
Solution Approach 1:
The invention precisely controls the macropore size parameter within 100-200nm and limits the volume ratio B/A to 3.0-5.0. This parameter control ensures macropores are large enough to buffer interlayer expansion effectively, improving cycle performance, but not so large or numerous that they significantly reduce the surface area available for lithium ion reactions, thereby maintaining kinetic performance.
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
This configuration improves battery kinetic performance by optimizing liquid absorption and electronic conductivity, while buffering structural expansion during cycling, thereby balancing energy density and kinetic performance.
Implementation Method 1
The mesoporous structure with a pore size of 2nm-50nm can effectively improve the liquid absorption capacity
Implementation Method 2
The mesoporous structure with a pore size of 2nm-50nm can effectively improve the liquid absorption capacity and electron conductivity
Data Source
AI summary
The present disclosure relates to a negative electrode active material, a negative electrode sheet, an energy storage device and an electricity-consumption device. The negative electrode active material includes: mesopores with a pore size of 2nm to 50nm and macropores with a pore size of 100nm to 200nm; a percentage of total mesopore volume is A, a percentage of total macropore volume is B, and B/A satisfies: 2.6≤B/A≤5.0.