Si Electrode Active Material Void Structure for Volume Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrode active materials, particularly those containing silicon (Si), experience significant volume changes during charge and discharge cycles, which can lead to material degradation and reduced battery performance.
Innovation Solution
Incorporating specific ratios of first and second voids within the primary particle structure of the Si-based electrode active material, with pore diameters ranging from 30 nm to 100 nm and 1 nm to 5 nm, respectively, to control and minimize volume changes during charge and discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Si is used as an electrode active material to increase energy density, then the battery capacity is improved, but the volume change during charge and discharge becomes large
Solution Approach 1:
The patent applies porous materials by introducing voids with specific pore diameters (10 nm to 100 nm) into the Si-based electrode active material. These voids act as buffer spaces that accommodate the volume expansion of Si during lithiation, reducing the overall volume change while maintaining high capacity. The porous structure allows the material to absorb expansion stress without structural collapse.
Solution Approach 2:
The patent uses composite materials by combining Si with a porous matrix or coating structure. This composite approach maintains the high capacity benefit of Si while the surrounding porous structure provides mechanical support and accommodates volume changes, effectively resolving the contradiction between high capacity and low volume change.
2Stability of the object's composition
If voids are introduced into the primary particle to restrain volume change, then the volume stability is improved, but the manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent applies parameter changes by specifying a particular range for pore diameter (10 nm to 100 nm) and void amount (0.03 cc/g to 0.30 cc/g). By optimizing these parameters within specific ranges, the patent achieves effective volume change restraint while making the manufacturing process controllable. The specific parameter ranges balance performance requirements with manufacturing feasibility.
3Stability of the object's composition
If the void amount is increased to further reduce volume change, then the volume stability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies partial action by introducing a moderate amount of voids (0.03 cc/g to 0.30 cc/g) rather than excessive porosity. This partial void introduction is sufficient to restrain volume change effectively while avoiding the manufacturing complexity and potential performance degradation that would result from excessive void content. The optimized void amount achieves the necessary volume stability without over-complicating the manufacturing process.
Data Source
AI summary
The present disclosure solves the above problem by providing an electrode active material that contains an Si element and that includes a void in the interior of a primary particle, in which: a first void having a pore diameter of 30 nm or more and 100 nm or less and a second void having a pore diameter of 1 nm or more and 5 nm or less are included as the void; and when the amount of the first void is A and the amount of the second void is B, the ratio (A/B) of the A to the B is more than 0.10 and less than 17.00.