Porous Carbonaceous Anode With Uniform Silicon in Activated Pores
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Solution Overview
Problem
Silicon-based anode materials in lithium ion batteries suffer from volume change during detachment/embedding, leading to particle pulverization, SEI film destruction, and rapid capacity degradation due to uneven activation and lack of uniformly distributed pores in porous carbon prepared by biomass methods.
Innovation Solution
An anode material with a porous carbonaceous structure where silicon is uniformly distributed, achieving a uniformity degree of ≥80%, ensuring silicon is mainly present in activated pores, thereby inhibiting volume expansion and improving cycling and rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If porous carbon is prepared by biomass method to deposit silicon, then silicon can be deposited in pores, but the porous carbon suffers from uneven activation and has poreless particles, leading to poor silicon distribution
Solution Approach 1:
The patent applies preliminary action by conducting a two-stage activation process where the first stage uses KOH activation to create initial pores, and the second stage uses H3PO4 activation to further develop and uniformize the pore structure. This preliminary pore development ensures that subsequent silicon deposition occurs uniformly across all particles, eliminating the poreless particles problem and achieving consistent silicon distribution throughout the porous carbon matrix.
2Stability of the object's composition
If silicon is deposited in porous carbon to inhibit volume expansion, then expansion performance improves, but uneven pore activation causes non-uniform silicon distribution, leading to poor cycling performance
Solution Approach 1:
The patent applies local quality by creating a uniform pore distribution throughout the porous carbon structure through the two-stage activation process. This ensures that every region of the material has access to activated pores for silicon deposition, rather than having some particles fully activated and others poreless. The result is locally uniform silicon distribution across all particles, which maintains volume expansion stability while achieving reliable cycling performance.
3Quantity of substance
If silicon material is deposited on particle surfaces due to lack of activated pores, then deposition occurs, but expansion performance, cycling performance, and rate performance degrade
Solution Approach 1:
The patent applies the porous materials principle by systematically creating and uniformizing the pore structure through two-stage activation. This ensures that silicon deposition occurs preferentially within the activated pores rather than on particle surfaces. The uniform pore distribution throughout all particles enables consistent silicon uptake, achieving high silicon deposition amounts while maintaining excellent rate performance through the accessible porous network.
Data Source
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AI summary
The present disclosure relates to anode material and lithium ion battery. The anode material includes a porous carbonaceous material. A silicon material is distributed inside the porous carbonaceous material. The anode material has a uniformity degree N, and N meets N≥80%. In a Backscattered Electron (BSE) diagram obtained by scanning the anode material using a Scanning Electron Microscope (SEM) in a BSE automatic brightness and contrast mode, in any one of 100 µm*100 µm regions, the number of particles of the anode material having first brightness is recorded as C1, the first brightness indicates the anode material with a gray value in the BSE diagram greater than or equal to 5500, the number of particles of the anode material having second brightness is recorded as C2, the second brightness indicates the anode material with the gray value in the BSE diagram less than 5500, the anode material has a uniformity degree N'=C2/(C2+C1)*100% in the region, and the uniformity degree N of the anode material is an arithmetic mean of at least 10 N's.