Pre-Lithiated Battery Electrodes Using Mg-Li Alloy Lithium Transfer
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Solution Overview
Problem
Conventional lithium ion batteries suffer from capacity fade due to the formation of a solid electrolyte interphase (SEI) layer on the anode, leading to irreversible lithium loss and reduced battery performance over time.
Innovation Solution
The method involves pre-lithiating lithium ion battery electrodes by electrochemically connecting a magnesium-lithium alloy to the electrodes, transferring lithium ions to the electrodes, and then disconnecting the alloy, forming a porous magnesium-rich microstructure with controlled lithium content to minimize capacity fade and maximize charge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extra lithium capacity is incorporated onto the positive electrode to compensate for initial lithium loss, then capacity fade is counteracted, but energy density is reduced and lithium plating occurs on the negative electrode
Solution Approach 1:
The patent applies preliminary action by pre-lithiating the negative electrode before battery operation. A lithium source is introduced that releases lithium ions during initial cycles to compensate for SEI formation losses. This preliminary lithium addition ensures the electrode is fully lithiated before normal operation, counteracting capacity fade without requiring excess lithium in the positive electrode, thereby maintaining energy density and preventing lithium plating.
2Reliability
If a lithium source is introduced to compensate for lithium loss, then irreversible capacity loss is minimized, but device complexity increases
Solution Approach 1:
The patent employs universality by using the positive electrode to serve multiple functions: it acts as both the active lithium source and the functional cathode. The positive electrode is designed with excess lithium capacity that is gradually released to compensate for negative electrode lithium loss during SEI formation. This multi-functional approach eliminates the need for separate lithium sources or additional components, maintaining simple battery structure while minimizing irreversible capacity loss.
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 lithium wastage, enhances battery capacity, and maintains efficiency by forming a protective SEI layer while minimizing lithium dendrite growth, thereby extending the battery's lifespan and driving range.
Implementation Method 1
pre-lithiating the electrode by transferring lithium ions from the magnesium-lithium alloy to the electrode
Implementation Method 2
transferred a substantial portion of the lithium from the lithium-containing alloy to the electrode material
Implementation Method 3
the formation of passive film known as solid electrolyte interphase (SEI) layer over the surface of the negative electrode (anode)
Data Source
AI summary
A method for making a pre-lithiated electrode for a lithium ion battery cell, a method for making a battery with a pre-lithiated electrode, and an electric vehicle with a pre-lithiated electrode are provided. An exemplary method for making a pre-lithiated electrode for a lithium ion battery cell includes electrochemically connecting a magnesium-lithium alloy to the electrode. Further, the method includes pre-lithiating the electrode by transferring lithium ions from the magnesium-lithium alloy to the electrode. Also, the method includes electrochemically disconnecting the magnesium-lithium alloy from the electrode.