RAx Crystal Phase Anode for Lithium-Ion Battery
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Solution Overview
Problem
Current anode active materials for lithium ion rechargeable batteries face challenges such as low charge/discharge capacity, poor cycle characteristics, and high rate performance due to issues like dendritic lithium formation, instability, and high reactivity, as well as significant volume changes during charge/discharge cycles, which lead to shorter battery life and safety concerns.
Innovation Solution
An anode active material comprising particles with a specific crystal phase represented by RAx, where R is a rare earth element like Sc or Y, and A is Si or Ge, with a composition ratio of 1.0≤x≤2.0, forming a matrix to absorb stress and improve cycle characteristics, combined with gas deposition for forming a uniform active material layer on a collector, enhancing adhesivity and electronic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as anode active material to provide ample battery capacity, then battery capacity is improved, but dendritic lithium precipitation occurs leading to short-circuiting and reduced charge/discharge efficiency
Solution Approach 1:
The patent uses a composite material consisting of rare earth element (R) and silicon (Si) or germanium (Ge) in a specific crystal phase (RAx where 1.0≤x≤2.0). This composite structure combines the high capacity benefit of silicon/tin with the stability of rare earth elements, achieving both high battery capacity and good cycle characteristics without dendritic lithium formation
Solution Approach 2:
The patent optimizes the composition parameter x in RAx to be within 1.0≤x≤2.0, which balances the capacity contribution from Si/Ge with the structural stability from rare earth elements. This parameter optimization resolves the contradiction between capacity and reliability
2Quantity of substance
If silicon or tin is used as anode active material to achieve large battery capacity, then battery capacity is improved, but volume expansion/shrinkage ratio increases causing disengagement from collector and shorter battery life
Solution Approach 1:
The patent creates a composite material where rare earth elements (R) form a matrix structure with silicon (Si) or germanium (Ge). The rare earth element component provides structural stability and suppresses volume expansion, while Si/Ge contributes high capacity. This composite approach resolves the contradiction between capacity and battery life
Solution Approach 2:
The rare earth element matrix in the RAx structure acts as a cushioning framework that accommodates the volume changes of Si/Ge during charge/discharge cycles. This pre-established structural buffer prevents disengagement from the collector and maintains battery life
3Duration of action of stationary object
If alloying silicon or tin with other elements is done to suppress expansion/shrinkage, then battery life is improved, but battery capacity decreases significantly
Solution Approach 1:
The patent optimizes the composition parameter x in RAx to be within 1.0≤x≤2.0, which ensures sufficient Si/Ge content to maintain high capacity while having enough rare earth elements to suppress volume expansion. This precise parameter control resolves the contradiction between battery life and 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
The solution provides excellent charge/discharge capacity, cycle characteristics, and high rate performance by balancing the composition of rare earth elements and Si/Ge, reducing volume changes and improving adhesivity, thus extending battery life and safety.
Implementation Method 1
forming a matrix to absorb stress and improve cycle characteristics
Implementation Method 2
combined with gas deposition for forming a uniform active material layer on a collector
Data Source
AI summary
Provided are an anode active material for lithium ion rechargeable batteries and an anode, which are capable, when used in a lithium ion rechargeable battery, of providing excellent charge/discharge capacity and cycle characteristics, and also high rate performance, as well as a lithium ion rechargeable battery using the same. The anode active material contains particles having a crystal phase represented by RAx, wherein R is at least one element selected from the group consisting of rare earth elements including Sc and Y but excluding La, A is Si and/or Ge, and x satisfies 1.0≤x≤2.0, and a crystal phase consisting of A. The material is thus useful as an anode material for lithium ion rechargeable batteries.