Silicon Anode Oxygen Gradient for Cycle Life
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Solution Overview
Problem
Current anodes with integrated current collectors and active material layers face challenges in inhibiting expansion and shrinkage, leading to poor cycle characteristics due to the separation of these components during charge and discharge cycles.
Innovation Solution
An anode design where the anode active material layer, containing silicon and oxygen, is alloyed with the current collector at the interface, with a controlled oxygen content gradient across the thickness direction, preventing separation and enhancing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode active material layer is integrated with the anode current collector, then electronic conductivity is improved, but expansion and shrinkage during charge and discharge causes separation between the layers
Solution Approach 1:
The patent applies local quality by creating a gradient oxygen concentration distribution within the anode active material layer. The oxygen concentration is higher near the current collector interface and lower toward the electrolyte interface, forming distinct regions with different properties. This gradient structure provides strong adhesion at the interface while maintaining the necessary electrochemical performance in the bulk, thus resolving the contradiction between integration and expansion/shrinkage stability.
Solution Approach 2:
The patent changes the chemical composition parameter (oxygen concentration) spatially within the active material layer. By controlling the oxygen concentration to decrease from the current collector side toward the electrolyte side, the material properties are optimized for both adhesion and electrochemical function, preventing separation during volume changes while maintaining conductivity.
2Quantity of substance
If high capacity anode materials like silicon or tin are used, then battery capacity is improved, but significant expansion and shrinkage during charge and discharge pulverizes the active material
Solution Approach 1:
The patent creates a non-uniform oxygen distribution within the silicon-based active material layer, with higher oxygen concentration near the current collector and lower concentration toward the electrolyte. This local variation in composition provides structural support where needed while maintaining the high capacity characteristics of silicon in the bulk, preventing pulverization during repeated expansion and shrinkage cycles.
Solution Approach 2:
The patent effectively creates a composite structure within the active material layer by varying the oxygen concentration, forming regions with different mechanical and electrochemical properties. This composite approach combines the high capacity of silicon with the structural stability provided by oxygen-containing phases, preventing material degradation while maintaining high battery capacity.
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
This design effectively inhibits expansion and shrinkage of the anode active material layer, thereby improving battery cycle characteristics and capacity retention.
Implementation Method 1
an anode active material layer which is provided on the anode current collector, and which is alloyed with the anode current collector at least in part of the interface with the anode current collector
Implementation Method 2
when the average oxygen content on the current collector side is A and the average oxygen content on the surface side is B where the anode active material layer is divided into two in the thickness direction, the average oxygen content on the current collector side A is larger than the average oxygen content on the surface side B
Data Source
AI summary
A battery capable of improving cycle characteristics is provided. An anode active material layer is alloyed with an anode current collector at least in part of the interface with the anode current collector. The anode active material layer contains silicon and oxygen as an element. The average oxygen content in the anode active material layer is 40 atom % or less. When the average oxygen content on the current collector side is A and the average oxygen content on the surface side is B where the anode active material layer is divided into two in the thickness direction, the average oxygen content on the current collector side A is larger than the average oxygen content on the surface side B, and the difference therebetween, A−B is from 4 atom % to 30 atom %.