Pre-Lithiated Porous Silicon Anode for Heat-Safe Fast Charging
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Solution Overview
Problem
Lithium-ion batteries face issues such as irreversible capacity loss, thermal runaway due to heat buildup during pre-lithiation, and lithium plating during fast charging, which affect their safety and efficiency, especially with silicon anodes experiencing volume expansion and short cycle life.
Innovation Solution
A battery design featuring a porous silicon anode lithiated with a lithium source, utilizing a printable lithium composition that forms a porous framework and conductive layer, reducing volume expansion and irreversible capacity losses, and enabling faster charging through improved lithium diffusion kinetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium powder is directly laminated to the anode surface for pre-lithiation, then capacity loss is compensated, but heat buildup occurs due to short circuit lithiation leading to thermal runaway
Solution Approach 1:
A polymer coating layer is introduced as an intermediary between the lithium powder and the anode surface. This coating allows controlled lithium ion diffusion while preventing direct contact that would cause short circuit lithiation and heat buildup. The polymer acts as a mediator that enables beneficial lithium transfer while blocking harmful direct reactions.
Solution Approach 2:
The patent employs porous structures in the pre-lithiation layer that allow lithium ions to diffuse through controlled pathways. The porosity enables lithium transport while the structured architecture prevents uncontrolled short circuiting, dissipating heat more effectively than direct lamination.
2Quantity of substance
If silicon anode material is used to increase capacity, then energy density is improved, but volume expansion up to 400% occurs during lithiation reducing cycle life
Solution Approach 1:
Silicon particles are embedded within a porous matrix structure that provides internal void space. As silicon expands during lithiation, the nested porous framework accommodates this volume change, preventing structural collapse and maintaining electrode integrity over multiple cycles.
Solution Approach 2:
A porous framework surrounds and supports the silicon anode material. This porous structure provides expansion space for the silicon particles during lithiation, accommodating up to 400% volume increase without compromising the overall electrode structure or electrical connectivity.
3Productivity
If fast charging is implemented to increase power output, then charging rate is improved, but lithium plating occurs on the anode surface causing short circuits
Solution Approach 1:
The anode surface is engineered with non-uniform properties - a porous pre-lithiation layer with specific polymer coating creates localized regions that promote uniform lithium ion distribution. This local structural modification ensures that during fast charging, lithium ions are evenly distributed rather than concentrating at specific sites where plating would occur.
Solution Approach 2:
The polymer-coated porous layer serves as an intermediary that regulates lithium ion flux during fast charging. It smooths out concentration gradients and prevents excessive local current density that would lead to lithium plating, enabling high charging rates without short circuit risks.
4Quantity of substance
If conventional pre-lithiation is used to compensate for irreversible capacity loss, then initial capacity is improved, but 10-20% capacity is consumed by SEI formation
Solution Approach 1:
The anode is pre-lithiated before battery assembly using a controlled polymer coating process. This preliminary action introduces excess lithium in a controlled manner, ensuring that when the battery operates, the SEI formation consumes only the pre-added lithium while the main capacity remains available for cycling.
Solution Approach 2:
The patent changes the form and delivery method of lithium - using stabilized lithium powder with polymer coating instead of conventional lithium foil or metal organic frameworks. This parameter change in lithium delivery enables precise control over the amount and location of pre-added lithium, optimizing compensation for SEI losses.
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 enhances lithium-ion battery performance by reducing irreversible capacity, mitigating thermal issues, and increasing charging rates, while maintaining safety through controlled lithium diffusion and heat dissipation, thus improving cycle life and energy density.
Implementation Method 1
lithium diffusing from the printable lithium composition into an anode active material
Implementation Method 2
The polymer material may form a polymer film on the surface of the electrode that acts as a lithiation control layer
Implementation Method 3
the lithium ions are transferred from the cathode to the anode through the electrolyte
Implementation Method 4
electrons are collected from the anode and pass to the cathode through an external circuit
Data Source
AI summary
A battery having a cathode and an anode with a three-dimensional porous framework. The anode includes an anode active material lithiated with a lithium source. The lithium particles from the lithium source are alloyed or intercalated with the anode active material during diffusion to form the three-dimensional porous framework. The porous framework provides reduced electrode deterioration due to volume expansion.