Battery Electrode Pore Structure for Faster Lithium-Ion Diffusion
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in achieving high performance due to non-uniform pore distribution in the electrode, leading to polarization and inefficient lithium ion diffusion, which affects charging and discharging efficiency.
Innovation Solution
The electrode for a secondary battery is designed with a specific pore structure that ensures uniform distribution of pores, defined by certain surface area and pore volume ratios, which enhances lithium ion diffusion and reduces polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pores are formed in the electrode to improve lithium ion diffusion, then diffusion performance is improved, but pore distribution uniformity deteriorates leading to polarization
Solution Approach 1:
The patent utilizes a porous electrode structure with carefully controlled pore characteristics. The electrode contains pores with specific volume (0.15-0.25 mL/g) and surface area (20-29 m²/mL) to facilitate lithium ion diffusion while maintaining structural integrity and uniform distribution throughout the electrode layer.
Solution Approach 2:
The patent optimizes specific parameters of the pore structure including pore volume (0.15-0.25 mL/g), pore surface area (20-29 m²/mL), and average pore diameter (10-50 nm) to achieve both improved diffusion performance and uniform pore distribution, resolving the contradiction between diffusion speed and distribution uniformity.
2Speed
If total pore volume is increased to improve diffusion performance, then lithium ion diffusion is enhanced, but electrode density decreases affecting energy density
Solution Approach 1:
The patent identifies and optimizes critical parameters including pore volume (0.15-0.25 mL/g), pore surface area (20-29 m²/mL), and average pore diameter (10-50 nm) to achieve the optimal balance between diffusion performance and energy density, preventing both excessive pore volume and insufficient diffusion capability.
Solution Approach 2:
The patent applies partial action by introducing a moderate, controlled amount of porosity (0.15-0.25 mL/g) rather than maximizing pore volume completely. This partial porosity is sufficient to enhance lithium ion diffusion while maintaining adequate electrode density for high energy density, avoiding the extremes of either too much or too little porosity.
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 uniform pore distribution improves high-rate charge/discharge performance and energy density, resulting in enhanced lithium ion diffusion and reduced polarization, thereby improving the battery's high-output characteristics.
Implementation Method 1
improve diffusion performance of lithium ions
Implementation Method 2
suppressing a polarization phenomenon caused by current non-uniformity
Data Source
AI summary
The present invention provides an electrode for a secondary battery that includes a current collector and an electrode active material layer that is formed on the current collector and contains an electrode active material, and satisfies Relational Expression 1, 7≤total surface area of active material particles per unit volume of electrode active material layer≤10 and Relational Expression 2, 20≤total surface area of effective pores per unit volume of electrode active material layer≤29.