Li-ion Battery Anode Coating for Dendrite Control
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Solution Overview
Problem
Lithium-ion batteries are susceptible to dendrite formation, which leads to safety risks and reduced lifespan due to non-uniform lithium deposition on the current collector, causing surface roughness and increased chances of internal shorts.
Innovation Solution
A smooth lithium layer is formed on the current collector using a thin coating material with high chemical affinity for lithium, such as indium oxide or zinc oxide, applied through sputtering or chemical deposition, preventing dendrite growth and improving anode morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used in the negative electrode to increase specific energy, then the specific energy increases significantly, but dendrite formation occurs leading to safety risks and reduced lifespan
Solution Approach 1:
A coating layer comprising metal fluoride, metal oxide, or metal sulfide is applied to the negative electrode current collector. This coating acts as an intermediary between the lithium metal and the current collector, providing a controlled interface that promotes uniform lithium deposition while preventing direct contact that would lead to dendrite formation. The coating materials have high affinity for lithium and facilitate smooth lithium layer formation during cycling.
2Use of energy by moving object
If high-capacity positive electrode materials such as lithium/sulfur are used to maximize energy density, then the specific energy exceeds 350 Wh/kg, but the battery remains susceptible to dendrite formation and thermal runaway
Solution Approach 1:
The coating on the negative electrode current collector is applied in advance before battery assembly and initial cycling. This preliminary coating establishes a protective and conductive interface that prevents dendrite formation from the outset. The coating materials (metal fluoride, oxide, or sulfide) are selected to have high lithium affinity, ensuring that during the first charge cycle, lithium deposits uniformly on the coating rather than forming dendrites directly on the current collector.
3Reliability
If conventional carbonaceous negative electrodes are used to ensure safety, then safety is maintained, but the specific energy is significantly lower compared to lithium metal electrodes
Solution Approach 1:
The invention changes the physical and chemical parameters of the negative electrode by applying a thin coating layer (5-50 nm thickness) of metal fluoride, oxide, or sulfide on the current collector. This coating modification transforms the electrode properties to enable lithium metal deposition while maintaining safety. The coating provides high electrical conductivity, high lithium affinity, and controlled morphology that enables lithium metal to be used safely, achieving specific energy >350 Wh/kg with improved safety compared to uncoated lithium electrodes.
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 extends the cycle life and safety of the battery by ensuring uniform lithium deposition, reducing the risk of internal shorts and thermal runaway.
Implementation Method 1
A smooth lithium layer is formed on the current collector using a thin coating material with high chemical affinity for lithium, such as indium oxide or zinc oxide, applied through sputtering or chemical deposition
Implementation Method 2
A smooth lithium layer is formed on the current collector using a thin coating material with high chemical affinity for lithium, such as indium oxide or zinc oxide, applied through sputtering or chemical deposition
Implementation Method 3
A smooth lithium layer is formed on the current collector using a thin coating material with high chemical affinity for lithium
Data Source
AI summary
An electrochemical cell in one embodiment includes a negative electrode including a form of lithium, a positive electrode spaced apart from the negative electrode, an electrolyte, a separator positioned between the negative electrode and the positive electrode, and a current collector in the negative electrode, the current collector including a substrate material and a coating material on the surface of the substrate material, wherein the coating material does not include a form of lithium.