Non-graphitizable Carbon Negative Electrode Pore Structure
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Solution Overview
Problem
Energy storage devices, such as lithium ion batteries, face challenges in achieving high power and durability when using non-graphitizable carbon as a negative active material, particularly due to limitations in pore size and volume which affect electrolyte diffusion and structural resistance.
Innovation Solution
The energy storage device incorporates a negative electrode with a non-graphitizable carbon active material layer having pores between 0.1 µm and 1.0 µm in size, a total pore volume of 0.26 cm³ to 0.46 cm³ per gram, and a 90% cumulative diameter (D90) of 1.9 µm to 11.5 µm, optimized through specific production conditions and the use of an aqueous binder, to enhance power and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If non-graphitizable carbon formed into particles having a small particle size is used as a negative active material, then the power of the energy storage device can be increased, but the durability may be insufficient
Solution Approach 1:
The invention uses non-graphitizable carbon particles with a specific pore structure (pore size 0.03-1.0 μm and pore volume 0.03-0.30 ml/g) as the negative active material. The porous structure allows efficient electrolyte penetration and ion transport while maintaining structural integrity, thereby achieving both high power and high durability simultaneously
Solution Approach 2:
The invention optimizes specific parameters of the non-graphitizable carbon particles, including pore size (0.03-1.0 μm), pore volume (0.03-0.30 ml/g), and particle size distribution (D90: 3.0-11.5 μm), to achieve the best balance between power and durability. By precisely controlling these parameters, the invention resolves the contradiction between high power and high durability
2Power
If the pore size and pore volume of the active material layer are increased to enhance electrolyte diffusion, then the power increases, but the structural resistance decreases
Solution Approach 1:
The invention employs non-graphitizable carbon particles with an optimized pore structure (pore size 0.03-1.0 μm, pore volume 0.03-0.30 ml/g) that provides sufficient electrolyte diffusion pathways while maintaining structural integrity. The specific pore size range ensures good electrolyte penetration without compromising the structural resistance of the active material layer
Solution Approach 2:
The invention creates different local structures within the active material layer by controlling the pore size distribution and particle size distribution (D90: 3.0-11.5 μm). The porous structure provides local regions for electrolyte diffusion while the overall particle structure maintains structural resistance, achieving both high power and structural integrity
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 enables the battery to maintain high power and durability by balancing electrolyte diffusion and structural resistance, with the specific pore volume and particle size distribution ensuring effective performance over time.
Implementation Method 1
the active material layer has pores having a pore size of 0.1 μm or more and 1.0 μm or less, a total volume of the pores is 0.26 cm³ to 0.46 cm³ per gram
Data Source
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AI summary
An energy storage device includes a positive electrode, a negative electrode, and a nonaqueous electrolyte solution. The negative electrode includes an active material layer, and the active material layer has pores having a pore size of 0.1 µm or more and 1.0 µm or less, and a total volume of the pores is 0.26 cm3/g or more and 0.46 cm3/g or less.