High-Density Negative Electrode Electrolyte for High-Voltage Li Batteries
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Solution Overview
Problem
Rechargeable lithium batteries face safety issues and reduced cycle-life due to side reactions and lithium dendrite growth under high-voltage conditions, with existing surface treatments offering inadequate protection for positive electrodes and deteriorating negative electrode capacity.
Innovation Solution
A rechargeable lithium battery design incorporating a high-density negative electrode with an electrolyte containing ethyl butyrate, a borate compound, and an Ag salt, which suppresses electrolyte discoloration and lithium dendrite generation, enhancing safety and cycle-life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-voltage driving conditions are used to achieve high energy density, then battery capacity and energy density are improved, but positive electrode deterioration and side reactions occur
Solution Approach 1:
The patent introduces an intermediary substance (electrolyte additive containing borate compound and Ag salt) that mediates between the high-voltage operating conditions and the electrode-electrolyte interface. This additive forms a protective interface layer that enables high-voltage operation while preventing direct harmful interactions between the electrolyte and electrodes, thus resolving the contradiction between energy density and safety.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by adding specific borate compound and Ag salt additives. This parameter change modifies the electrolyte's properties to be compatible with high-voltage operation, enabling the battery to operate at higher voltages without causing electrode deterioration or excessive side reactions.
2Reliability
If surface treatment is applied to protect electrodes from side reactions, then electrode protection is improved, but negative electrode capacity deteriorates
Solution Approach 1:
Instead of directly treating the negative electrode surface, the patent uses an intermediary electrolyte additive that forms a protective layer through chemical interaction in the electrolyte. This indirect approach provides electrode protection while avoiding the capacity loss associated with direct surface treatments.
Solution Approach 2:
The electrolyte additive performs self-protection by automatically forming a protective interface layer at the electrode surface through chemical reactions. This self-service mechanism provides continuous protection without requiring external surface treatment processes that would reduce electrode capacity.
3Speed
If conventional electrolyte is used to achieve high ion conductivity, then ion transport is improved, but electrolyte discoloration and lithium dendrite growth occur
Solution Approach 1:
The borate compound and Ag salt additives act as intermediaries that modify the electrolyte's behavior at the electrode interface. They form protective layers that maintain high ion conductivity while blocking the formation of lithium dendrites, thus resolving the contradiction between ion transport efficiency and dendrite suppression.
Solution Approach 2:
The patent creates a composite electrolyte system by combining conventional high-conductivity electrolyte components with borate compound and Ag salt additives. This composite approach maintains the beneficial high ion conductivity while adding the functional properties of dendrite suppression and discoloration prevention.
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 effectively secures battery safety and improves capacity and lifespan under high-voltage conditions by inhibiting electrolyte discoloration and lithium dendrite growth, thereby enhancing the overall performance of the battery.
Implementation Method 1
the additive includes a borate compound represented by Chemical Formula 1 and an Ag salt... suppresses or reduces discoloration of an electrolyte
Implementation Method 2
the additive includes a borate compound represented by Chemical Formula 1 and an Ag salt... suppresses or reduces generation of lithium dendrites in a negative electrode
Implementation Method 3
electrolytes play an important role of transporting lithium ions, wherein an electrolyte containing an organic solvent and a lithium salt may exhibit superbly high ion conductivity
Data Source
AI summary
Disclosed is a rechargeable lithium battery including a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, a separator between the positive electrode and the negative electrode, and an electrolyte, wherein a density of the negative electrode is greater than or equal to about 1.6 g/cc, the electrolyte includes a non-aqueous organic solvent, a lithium salt, and an additive, the non-aqueous organic solvent includes ethyl butyrate, and the additive includes a borate compound represented by Chemical Formula 1 and an Ag salt.