Pre-Lithiated Silicon Anode Cycling Window for Volume Expansion Control
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Solution Overview
Problem
Existing lithium secondary batteries with silicon-based active materials face significant challenges due to volume expansion during charging and discharging, leading to reduced life performance and electrode structure collapse.
Innovation Solution
A method involving pre-lithiation of the negative electrode with a silicon-based active material, followed by electrochemical charging and discharging within a specific SOC difference range of 18% to 32%, to stabilize the electrode structure and improve life performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based active material is used in the negative electrode to achieve high capacity and energy density, then the battery capacity increases significantly, but the electrode structure collapses due to volume expansion during charging and discharging
Solution Approach 1:
The patent applies pre-lithiation to the negative electrode before battery assembly, which compensates for the irreversible capacity loss and volume expansion issues of silicon-based materials. By introducing lithium in advance, the electrode structure is pre-stabilized to withstand subsequent expansion during cycling, thus maintaining both high capacity and structural integrity
Solution Approach 2:
The patent optimizes the SOC difference parameter to a specific range (15-30%) to control the electrochemical behavior of the pre-lithiated negative electrode. This parameter adjustment ensures that the electrode experiences controlled volume changes that prevent structural collapse while maintaining high capacity utilization
2Duration of action of stationary object
If the negative electrode is pre-lithiated to improve initial efficiency and life performance, then the battery life characteristics improve significantly, but the electrode structure may still collapse due to excessive volume expansion
Solution Approach 1:
The patent precisely controls the SOC difference parameter within 15-30% range during charging and discharging. This parameter optimization ensures that the pre-lithiated electrode undergoes controlled volume expansion that extends battery life without causing structural collapse, achieving both improved durability and structural stability
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 method enhances the initial efficiency and life performance of the negative electrode by minimizing volume expansion and maintaining a conductive network, thereby preventing electrode collapse and improving the overall battery performance.
Implementation Method 1
electrochemically charging and discharging the secondary battery with at least one cycle
Data Source
AI summary
Methods for charging and discharging a secondary battery are disclosed, which includes: pre-lithiating a negative electrode comprising a silicon-based active material; preparing a secondary battery including the pre-lithiated negative electrode, a positive electrode, a separator, and an electrolyte; and electrochemically charging and discharging the secondary battery with at least one cycle, wherein the electrochemical charging and discharging of the secondary battery is performed so that a difference between a charge SOC and a discharge state of charge (SOC) of the pre-lithiated negative electrode is 18% to 32%.