Coated Si Anode Material for Stable Solid-State Battery Cycling
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Solution Overview
Problem
Si-based active materials in anode layers of all solid state batteries experience significant volume change during charge and discharge cycles, leading to increased reaction resistance and capacity degradation due to cut-off of ion and electron conducting paths.
Innovation Solution
A coated anode active material is developed with a silicon oxide layer between a Si-based active material and a coating layer, which includes lithium oxide, enhancing adhesiveness and preventing reaction resistance increase during high cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Si-based active material is used to achieve high energy density, then capacity is improved, but reaction resistance increases during high cycles
Solution Approach 1:
A coating layer comprising lithium oxide is introduced as an intermediary substance between the Si-based active material and the electrolyte. This coating layer serves as a mediator that prevents direct harmful reactions while maintaining ionic conductivity, thereby suppressing reaction resistance increase during high cycles while preserving the high capacity benefits of Si-based materials.
Solution Approach 2:
The invention uses a composite structure where the Si-based active material is combined with a lithium oxide-containing coating layer. This composite material approach allows the system to benefit from both the high capacity of Si and the stability and ion conductivity of lithium oxide, resolving the contradiction between capacity and reaction resistance.
2Quantity of substance
If Si-based active material undergoes volume change during charge and discharge, then capacity is improved, but ion and electron conducting paths are cut off
Solution Approach 1:
The lithium oxide-containing coating layer acts as a flexible protective shell that can accommodate the volume changes of the Si-based active material during charge and discharge cycles. This shell maintains the integrity of ion and electron conducting paths despite the expansion and contraction of the underlying Si material, preventing path cutoff while preserving capacity.
Solution Approach 2:
The coating layer is applied beforehand to the Si-based active material to provide cushioning protection. This pre-applied layer prevents direct contact between the Si material and the electrolyte, and maintains conducting paths during volume changes, thereby preventing the harmful effects before they occur.
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 coated anode active material inhibits the increase in reaction resistance and maintains capacity by allowing the coating layer to follow the expansion and contraction of the Si-based active material, thereby maintaining ion and electron conductivity.
Implementation Method 1
the silicon oxide layer is arranged between the Si-based active material and the coating layer, and thus the adhesiveness of the Si-based active material with the coating layer improves
Implementation Method 2
the coating layer to follow the expansion and contraction of the Si-based active material, thereby maintaining ion and electron conductivity
Data Source
AI summary
A main object of the present disclosure is to provide a coated anode active material capable of preventing the reaction resistance from increasing during high cycles. The present disclosure achieves the object by providing a coated anode active material including: a Si-based active material; and a coating layer that coats at least a part of a surface of the Si-based active material and includes a lithium oxide; wherein a silicon oxide layer is formed between the Si-based active material and the coating layer.