Composite-Coated Silicon Anode for Expansion-Stable Li-Ion Cycling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing silicon-based anode materials for lithium-ion batteries suffer from severe volume expansion and poor conductivity, leading to low reversible capacity and poor cycle stability.
Innovation Solution
A silicon-based anode material coated with a composite layer comprising flake graphite, a flexible polymer, and nano-carbon based material, which synergistically inhibits expansion and enhances conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based material is used as anode material, then specific capacity is improved, but volume expansion effect occurs leading to poor cycle stability
Solution Approach 1:
The patent applies nesting by placing silicon-based particles inside a porous carbon matrix structure. The silicon particles are embedded within the three-dimensional porous carbon framework, allowing the carbon matrix to constrain silicon expansion while maintaining electrical contact. This nested configuration enables the high capacity of silicon to be utilized while the outer carbon structure provides structural stability during cycling.
Solution Approach 2:
The patent creates a composite material system combining silicon-based material with porous carbon matrix and conductive polymer coating. The composite structure integrates the high capacity advantage of silicon with the structural stability of carbon and the conductivity enhancement of polymer coating, resolving the contradiction between capacity and cycle stability.
2Reliability
If conductive polymer coating is applied through in-situ polymerization, then conductivity is improved, but the process becomes complicated and the coating is unstable
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing the conductive polymer and then uniformly coating it onto the silicon-based particles through dispersion and drying processes. This approach avoids the complexity of in-situ polymerization while ensuring stable and uniform conductivity coating on the particle surfaces.
3Reliability
If conductive agent is dispersed around active material, then conductivity is improved, but the conductive agent loses connection during cycling
Solution Approach 1:
The patent applies local quality by incorporating conductive polymer not just as external coating but also within the porous carbon matrix structure surrounding the silicon particles. This creates localized conductive pathways that remain stable during cycling, ensuring continuous electrical connection between active materials while maintaining high overall conductivity.
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 composite coating provides high electric conductivity, stability, and effective cyclic expansion inhibition, prolonging the service life of lithium-ion batteries.
Implementation Method 1
a composite layer coated on the surface of the silicon-based active material, where the composite layer comprises a flexible polymer and a conductive material
Implementation Method 2
the conductive material comprises flake graphite and a nano-carbon based material
Implementation Method 3
the composite layer... synergistically inhibits expansion
Data Source
AI summary
A silicon-based anode material, a preparation method therefor and a use thereof in a lithium-ion battery. The silicon-based anode material comprises a silicon-based active material and a composite layer that coats the surface of the silicon-based active material, wherein the composite layer comprises a flexible polymer, flake graphite and a conductive material. The preparation method according to the present application is simple, low cost, easy to be industrialized. The prepared silicon-based anode material has excellent electrochemical cycle performance and expansion inhibition and allows prolonged service life of lithium ion batteries.