Pre-lithiated Negative Electrode for Lithium Secondary Battery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face issues with initial irreversible phase formation during charging and discharging, leading to reduced efficiency and safety concerns, particularly with silicon-based negative electrode materials that exhibit significant volumetric expansion.
Innovation Solution
A method involving the formation of a lithium metal powder coating layer on a separator, which contacts the negative electrode active material, allowing for pre-lithiation and minimizing the formation of irreversible phases by forming a composite with the metalloid oxide, thereby enhancing the initial efficiency of the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If carbon coating is applied to silicon-based material to reduce volumetric expansion, then battery life is improved, but initial charging/discharging efficiency is lowered due to irreversible phase formation
Solution Approach 1:
The patent applies preliminary action by pre-compositing lithium with metalloid oxide before battery assembly. This pre-lithiation process occurs during manufacturing, so that when the battery undergoes initial charging/discharging, the irreversible phase formation is minimized because lithium is already present in the metalloid oxide structure, eliminating the need for lithium to be extracted from the electrolyte during initial cycles.
2Quantity of substance
If silicon-based material is used as negative electrode active material to increase capacity, then theoretical capacity is significantly improved, but volumetric expansion during charging/discharging causes capacity degradation and safety issues
Solution Approach 1:
The patent employs composite materials by creating a composite structure of lithium and metalloid oxide (such as SiOx). This composite material combines the high capacity benefits of silicon-based materials with the structural stability of metalloid oxide, allowing the silicon to expand and contract during lithium insertion/extraction without degrading the overall structure, thus maintaining both high capacity and good cycle characteristics.
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 approach reduces the generation of lithium oxide and lithium metal oxide during initial charging/discharging, improving the initial efficiency and cycle life of the lithium secondary battery by pre-forming lithium alloys with the negative electrode active material.
Implementation Method 1
coating the lithium dispersion on one side of a separator to form a lithium metal powder coating layer
Implementation Method 2
laminating the electrode assembly to transfer the lithium metal powder to the negative electrode
Implementation Method 3
lithium and metalloid oxide can be pre-lithiated simultaneously with the operation of the battery, thereby minimizing the formation of irreversible phases
Data Source
AI summary
A method for manufacturing a lithium secondary battery including a pre-lithiated negative electrode. A composite of lithium and a negative electrode active material is formed through a lamination process which is a process of manufacturing a battery. In the case of the lithium secondary battery to which the negative electrode having the composite formed by lithium and the negative electrode active material is applied, when the battery starts to operate, the negative electrode active material is pre-lithiated, and thus the charging/discharging process proceeds in the state where the lithium alloy is already formed on the negative electrode, thereby showing an effect of reducing initial irreversible phases.