Pre-Lithiated Li-Ion Electrodes With Gradient Lithium Transfer
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Solution Overview
Problem
Lithium-ion batteries face high first cycle active lithium losses due to solid electrolyte interphase formation, leading to decreased energy density and increased costs, as compensating with cathode active materials is ineffective and costly.
Innovation Solution
Pre-lithiation of electrodes by depositing a lithium layer on a current collector and calendering to transfer lithium to the electrode layer, creating a concentration gradient with higher lithium near the current collector, enhancing energy density and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cathode active materials are used to compensate for first cycle lithium loss, then lithium loss is compensated, but energy density decreases and cost increases
Solution Approach 1:
The patent applies preliminary action by pre-lithiating the anode before battery assembly. A lithium-containing layer is deposited on the anode current collector, and during calendering, lithium is transferred to the anode active material in advance. This pre-loading of lithium compensates for the first cycle loss before it occurs, eliminating the need to over-design the cathode with excess lithium, thereby maintaining high energy density while compensating for lithium loss.
Solution Approach 2:
The patent extracts the lithium compensation function from the cathode and relocates it to the anode. Instead of using additional cathode active material to compensate for lithium loss, the invention deposits a lithium-containing layer directly on the anode current collector, separating the compensation function from the cathode and placing it where it is most effective.
2Reliability
If cathode active materials are used to compensate for first cycle lithium loss, then lithium loss is compensated, but manufacturing cost increases
Solution Approach 1:
By performing preliminary lithium deposition on the anode current collector before assembly, the invention eliminates the need for costly cathode modifications. The lithium-containing layer is applied in advance using standard coating techniques, and the calendering process naturally transfers lithium during normal manufacturing, avoiding additional expensive materials or complex processing steps.
3Device complexity
If lithium is uniformly distributed in the electrode layer, then electrode structure is simple, but lithium transfer efficiency during calendering is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform lithium distribution with higher concentration near the current collector interface. The lithium-containing layer is deposited on the current collector surface, and calendering transfers lithium preferentially to the adjacent electrode material. This localized lithium enrichment at the interface maximizes transfer efficiency during calendering while maintaining a relatively simple overall electrode structure.
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 method results in improved energy density and cycle life while reducing costs by efficiently managing lithium distribution within the electrode, favoring fast charging and enhancing cell chemistry and safety.
Implementation Method 1
the layer comprising lithium is deposited via thermal evaporation
Implementation Method 2
the layer comprising lithium is deposited via e-beam evaporation
Implementation Method 3
the layer comprising lithium is deposited via sputtering
Implementation Method 4
the protection layer passivates the surface of the layer comprising lithium
Implementation Method 5
calendering the electrode-lithium coated current collector to transfer lithium from the lithium coated current collector to the electrode layer
Implementation Method 6
calendering the electrode-lithium coated current collector densifies the electrode-lithium coated current collector
Implementation Method 7
calendering the electrode-lithium coated current collector bonds the electrode layer to the lithium coated current collector
Data Source
AI summary
Provided are pre-lithiated electrodes, and systems and methods of making pre-lithiated electrodes. The pre-lithiated electrode can be formed from depositing an electrode layer on a lithium coated current collector to form an electrode-lithium coated current collector and calendering the electrode-lithium coated current collector to transfer lithium from the lithium coated current collector to the electrode layer to form the pre-lithiated electrode film. The pre-lithiated electrode film can have a greater concentration of lithium in a first portion of the electrode layer that is closer to the current collector than a second portion of the electrode layer that is farther from the current collector.