Lithium Metal Anode Electrolyte Coating for Dendrite Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges in controlling lithium metal deposition, leading to dendritic growth and increased side reactions, which decrease discharge capacity and cycle characteristics due to the inability to suppress dendritic deposition effectively with existing solutions.
Innovation Solution
Incorporating a non-aqueous electrolyte with a fluoroalcohol and an oxalate complex anion containing fluorine, which forms a flexible organic fluoride coating on the lithium metal surface, preventing dendritic deposition and enhancing cycle characteristics by interacting with the inorganic fluoride coating derived from the oxalate complex anion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as the negative electrode active material to achieve high theoretical capacity density, then the discharge capacity is improved, but the deposition form of lithium metal becomes difficult to control leading to dendritic growth
Solution Approach 1:
The patent introduces a fluoroalcohol as an intermediary substance in the non-aqueous electrolyte that mediates between the lithium metal deposition process and the electrolyte environment. This fluoroalcohol forms a protective coating on the lithium metal surface, acting as a mediator that prevents direct harmful interactions while allowing beneficial lithium ion transport, thereby controlling the deposition form and preventing dendritic growth
Solution Approach 2:
The patent modifies the chemical composition parameters of the non-aqueous electrolyte by incorporating a fluoroalcohol with specific molecular structure and properties. This parameter change in the electrolyte composition alters the deposition behavior of lithium metal, transforming the uncontrolled dendritic deposition into a more uniform and controlled deposition pattern
2Area of moving object
If lithium metal deposits in dendritic form, then the specific surface area of the negative electrode increases, but side reactions with the non-aqueous electrolyte increase causing capacity attenuation
Solution Approach 1:
The fluoroalcohol acts as a protective intermediary layer between the lithium metal surface and the non-aqueous electrolyte. This intermediary coating reduces direct contact between the electrolyte and lithium metal, thereby suppressing side reactions while maintaining the increased surface area benefits for charge/discharge capacity
Solution Approach 2:
The patent converts the potentially harmful effect of increased surface area (which leads to more side reactions) into a beneficial feature by using the fluoroalcohol coating to protect the enlarged surface area. The increased surface area provides higher capacity, while the fluoroalcohol coating prevents the corresponding increase in side reactions, thus converting what would be a harmful situation into a beneficial one
3Device complexity
If existing electrolyte compositions are used, then the battery structure is simple, but the charge/discharge cycle characteristics are insufficient
Solution Approach 1:
The patent creates a composite electrolyte system by combining fluoroalcohol with other non-aqueous electrolyte components. This composite electrolyte composition provides both the structural simplicity needed for manufacturing and the enhanced performance for charge/discharge cycle characteristics, achieving a balance between simplicity and durability
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 combination of fluoroalcohol and oxalate complex anion significantly suppresses dendrite generation, improving the charge/discharge cycle characteristics of lithium secondary batteries by forming a strong, flexible coating that adapts to surface changes, thereby maintaining discharge capacity and reducing side reactions.
Implementation Method 1
an oxalate complex anion including fluorine...which forms a flexible organic fluoride coating on the lithium metal surface
Implementation Method 2
the fluoroalcohol and oxalate complex anion significantly suppresses dendrite generation...by forming a strong, flexible coating that adapts to surface changes
Data Source
AI summary
A lithium secondary battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein in the negative electrode, lithium metal deposits during charging and the lithium metal dissolves during discharging, the non-aqueous electrolyte includes a fluoroalcohol, an oxalate complex anion including fluorine, a lithium ion, and a non-aqueous solvent.