Pre-lithiated Anode Lithiation Process for Battery Cycle Life
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Solution Overview
Problem
Rechargeable lithium ion batteries face significant irreversible losses due to passivation film formation and cathode passivation, leading to reduced cycle life and increased battery weight, as the cathode must be oversized to compensate for these losses, making the battery heavier and more expensive.
Innovation Solution
A novel roll-to-roll compatible lithiation process using inexpensive Li-bearing salts in non-aqueous solvents, such as LiCl, LiBr, and LiF, with gamma-butyrolactone and sparged gases like CO2, to electrochemically introduce lithium into the anode, forming a high-quality SEI layer and increasing lithiation efficiency, thereby reducing the need for excess cathode material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the cathode is oversized to compensate for irreversible metal ion losses, then the battery can support long cycle life, but the total weight of the battery increases
Solution Approach 1:
The patent applies preliminary action by introducing lithium metal into the anode before battery operation begins. This pre-lithiation process adds excess lithium to the anode structure, which then compensates for the irreversible lithium losses that occur during initial cycling and passivation layer formation. The anode is prepared in advance with additional lithium reservoirs that become available during subsequent charge-discharge cycles, eliminating the need for oversized cathode design.
Solution Approach 2:
The patent changes the lithium content parameter of the anode by incorporating stabilized lithium metal powder (SLMP) at controlled concentrations (typically 1-10 wt% of the anode mass). This parameter change increases the available lithium inventory in the anode, allowing the battery to maintain long cycle life without requiring increased cathode mass. The specific lithium addition amount can be optimized based on the desired cycle life and capacity requirements.
2Quantity of substance
If stabilized lithium metal powder is mixed into carbon before activation, then lithium can be sourced to the anode, but the material is very expensive and difficult to distribute evenly
Solution Approach 1:
The patent uses carbon materials as an intermediary carrier for the stabilized lithium metal powder. The SLMP is mixed with carbon precursors (such as carbon black, graphite, or amorphous carbon) before activation, allowing the lithium to be distributed throughout the anode structure in a controlled manner. The carbon matrix acts as a protective medium that prevents premature lithium oxidation while enabling even distribution during the mixing and activation processes. This intermediary approach simplifies manufacturing compared to direct lithium metal handling.
3Quantity of substance
If lithium metal foil is placed on current collector to form anode, then specific capacity is highest, but the cost of lithium metal foil is fairly high
Solution Approach 1:
The patent replaces expensive lithium metal foil with a more cost-effective stabilized lithium metal powder formulation. The SLMP can be produced at lower cost through controlled stabilization processes and can be incorporated into the anode during standard manufacturing operations. While lithium metal foil provides high specific capacity, the patent achieves comparable or sufficient capacity at reduced material cost and manufacturing complexity by using powder form with carbon matrix support.
Solution Approach 2:
The patent creates a composite anode material system combining stabilized lithium metal powder with carbon matrices and conductive additives. This composite approach distributes the lithium content throughout the anode structure, providing both high capacity and improved manufacturing characteristics. The composite formulation allows for better dispersion, enhanced conductivity, and simplified processing compared to pure lithium metal foil, while maintaining high lithium inventory for long cycle operation.
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 process enhances the reversible capacity and cycle life of lithium ion batteries by providing a surplus of lithium, reducing the weight and cost of the cathode, and improving the specific and volumetric capacity density of the battery.
Implementation Method 1
applying a reducing current to the anode and an oxidizing current to the field plate, wherein metal ions from the bath lithiate the anode
Implementation Method 2
A bath containing gamma butyrolactone (GBL), and at least one dissolved lithium halide salt such as, but not limited to LiCl, contacts the anode
Data Source
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AI summary
The present invention relates to a method for lithiation of an intercalation-based anode or a non-reactive plating-capable foil or a reactive alloy capable anode, whereby utilization of said lithiated intercalation-based anode or a plating-capable foil or reactive alloy capable anode in a rechargeable battery or electrochemical cell results in an increased amount of lithium available for cycling, and an improved reversible capacity during charge and discharge.