Porous Doped Negative Electrode for Li-Ion Capacity and Rate Balance
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Solution Overview
Problem
Current electrochemical apparatuses, such as lithium-ion batteries, face challenges in enhancing cycling performance and energy density due to limitations in negative electrode active materials, particularly in lithium ion intercalation and deintercalation efficiency and capacity.
Innovation Solution
A negative electrode active material layer is developed, comprising a combination of porous and nonporous portions with heteroatoms like boron, nitrogen, fluorine, or sulfur, which improve lithium ion intercalation efficiency and increase capacity by optimizing the interface and pore structure, along with a specific surface area and porosity range, to enhance energy density and rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the negative electrode active material uses conventional structure without porous portions, then the manufacturing process is simple, but the lithium ion intercalation and deintercalation efficiency is low
Solution Approach 1:
The negative electrode active material particle is designed with a porous portion that has a pore diameter of 0.1 μm to 3 μm, creating channels for efficient lithium ion transport. This porous structure significantly improves lithium ion intercalation and deintercalation efficiency while maintaining a manageable structural complexity through controlled pore formation.
2Productivity
If the porous portion area ratio is increased to improve rate performance, then the rate performance increases, but the energy density decreases
Solution Approach 1:
The area ratio of the porous portion to the nonporous portion is optimized within the range of 0.05 to 0.30, and the pore diameter is controlled at 0.1 μm to 3 μm. This parameter optimization achieves a balance between rate performance (improved by porous structure) and energy density (maintained by limiting the excessive porous portion).
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 proposed solution significantly increases the energy density and rate performance of electrochemical apparatuses by improving lithium storage performance and reducing internal resistance, while maintaining structural stability and minimizing adverse effects from heteroatoms.
Implementation Method 1
The porous portion improves the lithium ion intercalation and deintercalation efficiency
Implementation Method 2
when the negative electrode active material particles are doped with element boron, nitrogen, fluorine, phosphorus, or sulfur, these doping elements can be bonded with Li+ to increase the capacity
Data Source
AI summary
A negative electrode includes a negative electrode active material layer, the negative electrode active material layer includes negative electrode active material particles, and the negative electrode active material particle includes a porous portion and a nonporous portion with heteroatoms. The heteroatom includes at least one of element boron, nitrogen, fluorine, phosphorus, or sulfur and is located on an interface, and the interface is a region, in the nonporous portion, formed from a bordering position between the nonporous portion and the porous portion to 0.5 μm from the bordering position. The porous portion improves the lithium ion intercalation and deintercalation efficiency. In addition, boron, nitrogen, and other elements doped increase the gram capacity of the negative electrode active material, helping increase the energy density of the electrochemical apparatus.