Skeleton-Layer Lithium Anode and Electrolyte for Uniform Deposition
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Solution Overview
Problem
Lithium metal batteries face challenges in cycle performance due to lithium dendrite formation, uneven current distribution, and safety hazards such as short circuits, which are not adequately addressed by existing technologies.
Innovation Solution
An electrochemical device with an anode featuring a skeleton layer and insulation layer, combined with an electrolyte comprising a sulfone compound, a phosphorus compound, and a fluoroether compound, which stabilizes lithium deposition and reduces dendrite growth, enhancing cycle life and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte compositions are used in lithium metal batteries, then the battery can operate with basic functionality, but lithium dendrite formation occurs and cycle performance deteriorates
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating specific additives (cyclic carboxylate and cyclic carbonate) in optimized concentration ranges (0.1-5 wt% and 1-10 wt% respectively). This parameter change in chemical composition alters the deposition behavior of lithium, transforming it from dendritic growth to uniform plating, thereby resolving the contradiction between maintaining battery functionality and preventing harmful dendrite formation while improving cycle performance
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: cyclic carboxylate additives, cyclic carbonate additives, and base electrolyte solvents (ether or carbonate-based). This composite approach synergistically combines the benefits of each component - the cyclic carboxylate forms protective films, the cyclic carbonate enhances stability, and the base solvent provides ionic conductivity - collectively preventing dendrite formation and improving cycle performance without sacrificing battery operation
2Quantity of substance
If lithium metal is used as anode to achieve high energy density, then capacity increases, but safety hazards such as short circuits and thermal runaway increase
Solution Approach 1:
The patent applies preliminary action by having the cyclic carboxylate and cyclic carbonate additives pre-form protective interfacial films on the lithium metal anode surface during initial cycles. These pre-formed films act as stable solid electrolyte interphase (SEI) layers that prevent direct contact between the reactive lithium metal and the electrolyte, thereby eliminating safety hazards like short circuits and thermal runaway while preserving the high energy density benefits of lithium metal
Solution Approach 2:
The patent introduces cyclic carboxylate and cyclic carbonate additives as intermediary substances that mediate the interaction between lithium metal and the electrolyte. These intermediaries form stable interfacial layers that act as protective barriers, preventing harmful direct reactions while allowing ionic transport. This intermediary mechanism maintains the high capacity of lithium metal anodes while eliminating safety hazards associated with direct lithium-electrolyte contact
3Stability of the object's composition
If lithium deposition is uneven, then current distribution becomes non-uniform, but this leads to accelerated dendrite growth and reduced battery life
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by adding cyclic carboxylate (0.1-5 wt%) and cyclic carbonate (1-10 wt%) additives. This parameter modification alters the interfacial chemistry at the lithium anode, promoting uniform lithium ion flux distribution and enabling homogeneous lithium deposition. The resulting uniform current distribution prevents localized hotspots and accelerates dendrite growth, thereby extending battery life while maintaining compositional stability
4Reliability
If the solid electrolyte interfacial film is unstable, then lithium dendrites can pierce through, but this causes short circuits and reduces safety
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by incorporating cyclic carboxylate (0.1-5 wt%) and cyclic carbonate (1-10 wt%) additives. These compositional changes enable the formation of a stable solid electrolyte interfacial film with appropriate mechanical and chemical properties. The stabilized film acts as a robust barrier that prevents dendrite penetration, thereby improving safety while maintaining film stability over extended cycling
Solution Approach 2:
The patent creates a composite interfacial film structure through the synergistic interaction of cyclic carboxylate and cyclic carbonate additives with the base electrolyte. This composite SEI film combines the advantages of each component - cyclic carboxylate provides mechanical strength and dendrite resistance, while cyclic carbonate contributes to chemical stability and ionic conductivity. The composite structure achieves both enhanced safety by preventing dendrite piercing and improved long-term stability
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 significantly improves lithium metal battery cycle performance and safety by promoting uniform lithium deposition, reducing dendrite formation, and enhancing the stability of the solid electrolyte interfacial film, leading to longer cycle life and reduced risk of thermal runaway.
Implementation Method 1
stabilizes lithium deposition and reduces dendrite growth
Implementation Method 2
enhancing the stability of the solid electrolyte interfacial film
Data Source
AI summary
An electrochemical device including an anode having an anode current collector and a skeleton layer, the skeleton layer being disposed in an central region on the anode current collector, and a region, not covered by the skeleton layer, on the anode current collector being provided with an insulation layer; a cathode; and an electrolyte including about 1 wt % to about 40 wt % of a sulfone compound, about 1 wt % to about 40 wt % of a phosphorus compound and about 1 wt % to about 70 wt % of a fluoroether compound, based on the total weight of the electrolyte. The electrochemical device has superior cycle performance and safety performance.