Prelithiated Anode Chemistry for Uniform Lithium Insertion
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high initial coulombic efficiency and energy density due to irreversible electrochemical reduction of electrolytes forming a solid-electrolyte interphase (SEI) on the anode, which consumes active lithium ions, particularly in next-generation anode materials like silicon and silicon oxides, leading to lower energy density and stability issues.
Innovation Solution
A prelithiation solution using a lithium organic complex of an aromatic hydrocarbon derivative with a non-hydrogen substituted benzene ring is applied to chemically prelithiate the anode, providing a low redox potential for uniform lithium insertion and forming a protective film, thereby enhancing electrochemical reversibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solid lithium particles or lithium compounds are added as sacrificial lithium sources, then active lithium ion loss is compensated, but nanosized additives are difficult to synthesize at larger scale and lead to impurities in the electrode
Solution Approach 1:
The patent extracts the lithium source from solid particles or compounds and transforms it into a soluble lithium salt form that can be uniformly distributed in the electrode slurry, eliminating synthesis difficulties and impurity issues while maintaining the function of compensating active lithium loss
Solution Approach 2:
The patent changes the physical and chemical parameters of the lithium source by using soluble lithium salts instead of insol Solid lithium particles or compounds, enabling easy mixing, uniform distribution, and scalable production without impurity formation
2Quantity of substance
If lithium metal is directly applied to prelithiate the electrode, then active lithium is added, but it is difficult to precisely control the doping amount of lithium in the electrode
Solution Approach 1:
The patent replaces the mechanical/physical method of direct lithium metal contact with a chemical method using soluble lithium salts, allowing precise control of lithium doping amount through solution concentration and immersion time rather than relying on difficult-to-control physical contact
Solution Approach 2:
The patent introduces a soluble lithium salt solution as an intermediary medium between the lithium source and the electrode, enabling controlled and uniform lithium transfer while precisely controlling the doping amount through solution parameters
3Quantity of substance
If conventional prelithiation methods are used, then active lithium loss is compensated, but additional battery re-assembly step is required which is not suitable for commercialization
Solution Approach 1:
The patent merges the prelithiation step with the existing electrode preparation process by incorporating soluble lithium salt addition into the slurry mixing stage, eliminating the need for separate battery disassembly and re-assembly operations and enabling direct commercial production
4Quantity of substance
If silicon and silicon oxides are used as anode materials, then high capacity is achieved, but initial coulombic efficiency is lower than 80% due to SEI formation
Solution Approach 1:
The patent applies preliminary action by adding soluble lithium salts to the electrode slurry before electrode formation, ensuring that active lithium is pre-loaded into the electrode structure, thereby compensating for the lithium consumed during SEI formation and achieving high initial coulombic efficiency
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 achieves an ideal initial coulombic efficiency exceeding 100% and improves the energy density of lithium-ion batteries, with the prelithiated anode being suitable for large-scale production and maintaining stability in dry air.
Implementation Method 1
a step of preparing a prelithiated anode by immersing the anode in a prelithiation solution comprising a lithium organic complex of an aromatic hydrocarbon derivative
Implementation Method 2
irreversible electrochemical reduction of electrolytes occurs, which forms a solid-electrolyte interphase (SEI) on an anode in the initial cycle
Data Source
AI summary
The present disclosure relates to a prelithiation solution and a method for preparing a prelithiated anode using the same. The prelithiation solution and the method for preparing a prelithiated anode using the same according to the present disclosure allow uniform intercalation of lithium ions throughout the anode chemically in a solution via a simple process of immersing the anode in a prelithiation solution having a sufficiently low redox potential as compared to an anode active material. A prelithiated anode prepared by this method has an ideal initial coulombic efficiency and a lithium secondary battery with a high energy density can be prepared based thereon. In addition, the prepared anode is advantageously applicable to large-scale production due to superior stability even in dry air.