Lithium-Ion Battery Electrolyte with Sulfone Compounds for Thick Anode Stability
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in maintaining high cycle characteristics when the thickness of the anode active material layer is increased, leading to reduced intercalation efficiency and potential internal short circuits due to lithium dendrite formation and electrolyte decomposition.
Innovation Solution
Incorporating sulfone compounds in the electrolytic solution, specifically those represented by Chemical formulas 1 and 2, which form a protective coat on the anode and cathode surfaces, enhancing intercalation efficiency and inhibiting electrolyte decomposition, even when the anode active material layer thickness exceeds 30 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the anode active material layer is increased to obtain higher capacity, then the energy density is improved, but the intercalation efficiency of lithium ions is lowered and cycle characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the electrolytic solution. Specifically, it uses a mixture of cyclic carbonate (15-40 wt%), chain carbonate (30-60 wt%), and cyclic carboxylate (5-20 wt%) in optimized proportions. This parameter optimization allows the system to achieve both high capacity (through adequate anode layer thickness) and good cycle characteristics (through improved lithium ion intercalation efficiency enabled by the optimized electrolyte composition).
Solution Approach 2:
The patent employs composite materials by creating a multi-component electrolytic solution system that combines different types of carbonates and carboxylates. This composite electrolyte formulation (mixing cyclic carbonate, chain carbonate, and cyclic carboxylate) works synergistically to provide both the ionic conductivity needed for thick anode layers and the intercalation efficiency required for good cycle life, thus resolving the contradiction between capacity and reliability.
2Quantity of substance
If the volume density of the anode active material layer is increased to obtain higher capacity, then the energy density is improved, but the impregnation characteristics of the electrolytic solution are lowered and cycle characteristics deteriorate
Solution Approach 1:
The patent addresses this contradiction by changing the physical-chemical parameters of the electrolytic solution, specifically its viscosity and dielectric constant, through the selection of chain carbonate (which reduces viscosity) and cyclic carbonate/cyclic carboxylate (which increase dielectric constant). This parameter optimization enables the electrolyte to effectively impregnate high-volume-density anode structures while maintaining good lithium ion transport and cycle characteristics.
Solution Approach 2:
The composite electrolytic solution comprising cyclic carbonate, chain carbonate, and cyclic carboxylate in specific ratios creates a balanced system where the chain carbonate component ensures low viscosity for good impregnation, while the cyclic components provide high dielectric constant for efficient ion transport. This composite approach enables high volume density anodes to achieve both high capacity and good cycle life.
3Reliability
If chain ester carbonate (low-viscosity solvent) is used to improve intercalation efficiency of lithium ions, then the intercalation efficiency is improved, but the secondary battery is easily swollen due to gas generation and cycle characteristics are lowered
Solution Approach 1:
The patent resolves this contradiction by using a composite electrolytic solution that combines chain carbonate (which provides low viscosity and good intercalation efficiency) with cyclic carbonate and cyclic carboxylate (which provide high dielectric constant and electrochemical stability). The synergistic interaction of these components allows the system to achieve both excellent lithium ion intercalation efficiency and good cycle characteristics without excessive gas generation or battery swelling.
Solution Approach 2:
The patent optimizes the concentration parameters of the electrolytic solution components, specifically limiting chain carbonate to 30-60 wt% and adding cyclic carboxylate (5-20 wt%) to balance the system. This parameter control ensures that the low-viscosity chain carbonate provides good intercalation efficiency while the cyclic components suppress gas generation and improve overall stability, thereby maintaining good cycle characteristics.
4Quantity of substance
If the thickness of the anode active material layer is increased and volume density is increased, then higher capacity is obtained, but lithium dendrite precipitation occurs and internal short circuit may be generated
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolytic solution to create a more stable lithium ion transport environment. The optimized mixture of cyclic carbonate (15-40 wt%), chain carbonate (30-60 wt%), and cyclic carboxylate (5-20 wt%) provides uniform ionic conductivity and stable solvation shells around lithium ions, which promotes uniform deposition and prevents dendrite formation even in thick, high-volume-density anode structures.
Solution Approach 2:
The composite electrolytic solution acts as a stabilizing medium that combines the low-viscosity properties of chain carbonate (which allows uniform ion distribution) with the high dielectric constant and stability of cyclic carbonate and cyclic carboxylate. This composite system creates a stable electrochemical environment that suppresses lithium dendrite precipitation, enabling the use of thick anode active material layers with high volume density without the harmful effects of dendrite formation and internal short circuits.
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 use of sulfone compounds in the electrolytic solution improves lithium ion intercalation efficiency and prevents electrolyte decomposition, thereby maintaining high discharge capacity retention and cycle characteristics, even with increased anode active material layer thickness.
Implementation Method 1
Incorporating sulfone compounds in the electrolytic solution, specifically those represented by Chemical formulas 1 and 2, which form a protective coat on the anode and cathode surfaces, enhancing intercalation efficiency and inhibiting electrolyte decomposition
Implementation Method 2
a secondary battery using insertion and extraction of lithium (Li) for charge and discharge reaction
Implementation Method 3
a secondary battery using insertion and extraction of lithium (Li) for charge and discharge reaction
Data Source
AI summary
A battery capable of improving the cycle characteristics even if the thickness of an anode active material layer is increased is provided. The battery includes a cathode, an anode and an electrolytic solution. The anode has an anode active material layer on an anode current collector, and the anode active material layer contains a carbon material and has a thickness of 30 μm or more. The electrolytic solution contains a solvent and an electrolyte salt, and the solvent contains at least one of sulfone compounds such as a cyclic disulfonic acid anhydride.