Pre-lithiated Anode with Stabilized Lithium Particles
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Solution Overview
Problem
Lithium ion batteries face significant first cycle irreversible capacity loss due to the formation of a solid electrolyte interphase and other irreversible reactions at the anode, which increases costs and dead weight, and the direct use of lithium metal as an anode is unsafe due to dendrite formation, while existing methods for prelithiation and stabilization of lithium metal powder are difficult to scale up.
Innovation Solution
A poly(arylene oxide) binder is used to create a stable and scalable pre-lithiated anode composition with stabilized lithium metal particles coated with a lithium salt, dispersed throughout the anode material, allowing for the formation of a slurry that can be coated onto a metal substrate and activated to minimize first cycle irreversible capacity loss and enable the use of non-lithiated cathodes in lithium secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is directly used as an anode to enable non-lithiated high capacity cathode materials, then energy density is enhanced, but dendrite formation causes safety issues and cell shorts
Solution Approach 1:
The anode is prelithiated before battery assembly by coating stabilized lithium metal particles onto the anode laminate surface, then removing residual lithium foil. This preliminary lithiation provides excess lithium to compensate for first cycle irreversible capacity loss, enabling the use of non-lithiated high capacity cathode materials while preventing dendrite formation through controlled lithium distribution
Solution Approach 2:
The invention changes the physical state and distribution of lithium in the anode by using stabilized lithium metal particles with controlled size (less than 200 μm) and coating them with protective layers (lithium salt or wax). This transforms lithium from a bulk metal form prone to dendrites into a dispersed particle system that provides uniform lithium distribution and reduces dendrite formation risk
2Loss of energy
If n-butyllithium is added onto an anode laminate for prelithiation, then first cycle irreversible capacity loss is removed, but the process is difficult to scale up for industrial fabrication
Solution Approach 1:
The invention extracts and eliminates the problematic chemical lithiation step using n-butyllithium, replacing it with a physical coating process using stabilized lithium metal particles. This removes the need for hazardous chemical reactions and complex washing steps, making the process suitable for industrial scaling while still achieving the goal of compensating for first cycle capacity loss
Solution Approach 2:
The invention uses inexpensive, stable lithium metal particles that can be directly coated and processed without requiring complex chemical synthesis or purification steps. The stabilized particles serve as a disposable, easy-to-handle alternative to reactive organolithium compounds, enabling simple industrial fabrication processes
3Loss of energy
If lithium foil is attached onto the anode laminate surface for prelithiation, then first cycle irreversible capacity loss is removed, but residual lithium foil removal and process control are complex
Solution Approach 1:
The stabilized lithium metal particles are pre-coated onto the anode laminate surface before battery assembly, providing controlled excess lithium to compensate for first cycle irreversible capacity loss. The protective coating on the particles allows for controlled reaction, eliminating the need for subsequent removal steps required when using bulk lithium foil
Solution Approach 2:
The invention applies lithium in the form of stabilized particles with protective coatings only where needed on the anode surface, rather than using bulk lithium foil that requires extensive handling and removal. The local application of coated particles simplifies the process by eliminating the need for residual lithium removal steps while still achieving the desired lithiation effect
4Quantity of substance
If stabilized lithium metal powder coated with lithium salt is used, then lithiation can be achieved, but the lithium salt coating is incompatible with common solvents like NMP, DMF, and DMA
Solution Approach 1:
The protective coating on the stabilized lithium metal particles acts as an intermediary layer that prevents direct contact between the lithium salt and incompatible solvents like NMP, DMF, and DMA. This intermediary coating allows the particles to be processed in these common solvents without causing exothermic reactions, enabling slurry preparation and industrial fabrication
Solution Approach 2:
The invention changes the surface properties of the lithium metal particles by coating them with protective layers (lithium salt or wax). This modifies the interaction between the lithium particles and solvents, transforming the system from one that causes dangerous exothermic reactions to one that is compatible with common industrial solvents, enabling easy slurry preparation and processing
5Quantity of substance
If surface spray coating is used to apply SLMPs onto anode laminate, then prelithiation is achieved, but the technique suffers from clogging issues and is difficult to scale up
Solution Approach 1:
The invention replaces the surface spray coating technique with a slurry-based coating process that uses liquid media to transport and deposit stabilized lithium metal particles onto the anode laminate. This hydraulic approach eliminates the pneumatic clogging issues associated with spray techniques while enabling continuous processing and industrial scaling
Solution Approach 2:
The slurry acts as an intermediary medium that facilitates the uniform distribution and deposition of stabilized lithium metal particles onto the anode surface. The liquid slurry allows for easy processing, coating, and drying without the clogging problems of spray techniques, enabling scalable industrial fabrication while achieving uniform lithium particle coverage
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 solution results in minimal or no first cycle irreversible capacity loss and stable cycling performance with reversible specific capacity, enabling the production of high capacity lithium secondary batteries using pre-lithiated anodes with non-lithiated cathodes, addressing scalability and safety issues associated with previous methods.
Implementation Method 1
A poly(arylene oxide) binder is used to create a stable and scalable pre-lithiated anode composition
Implementation Method 2
The anode is then prelithiated in situ upon addition of an electrolyte
Data Source
AI summary
An electroactive composition includes an anodic material; a poly(arylene oxide); and stabilized lithium metal particles; where the stabilized lithium metal particles have a size less than about 200 μm in diameter, are coated with a lithium salt, are present in an amount of about 0.1 wt % to about 5 wt %, and are dispersed throughout the composition. Lithium secondary batteries including the electroactive composition along with methods of making the electroactive composition are also discussed.