Lithium-Ion Battery Electrolyte for Stable High-Nickel Interfaces
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Solution Overview
Problem
Lithium-ion batteries with high nickel content electrodes face challenges in structural stability, high-temperature performance, and cycle life due to increased nickel content, which requires an electrolyte that forms a stable interface film and suppresses cell expansion while maintaining low impedance for efficient lithium ion conduction.
Innovation Solution
The use of a synergistic combination of cyclic sulphonate and lithium (oxalato)borate additives in the electrolyte to form a uniform, chemically stable, and low-impedance interface film on the electrodes, reducing DCR growth and improving high-temperature and power performance of lithium-ion batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the content of element nickel in the positive electrode active material is increased to achieve high energy density, then the specific energy is improved, but the structural stability deteriorates and high-temperature performance worsens
Solution Approach 1:
The patent introduces an electrolyte as an intermediary medium between the high-nickel positive electrode and the environment. The electrolyte contains specific additives (cyclic carboxylate and lithium oxalate) that mediate the interaction at the electrode interface, forming protective films that stabilize the high-nickel material without changing the material composition itself. This allows the high-energy-density electrode to operate stably by managing its interface environment.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by introducing specific cyclic carboxylate compounds (with n=1-4 and specific R1 groups) and lithium oxalate in controlled concentrations (0.01-5% and 0.01-1% respectively). These parameter changes in the electrolyte composition lead to fundamental changes in the interface film properties, transforming it from an unstable to a stable configuration that can support high-nickel electrodes.
2Use of energy by moving object
If the content of element nickel in the positive electrode active material is increased to achieve high energy density, then the specific energy is improved, but the high-temperature performance deteriorates
Solution Approach 1:
The electrolyte acts as a thermal intermediary that protects the high-nickel electrode from direct exposure to harsh thermal environments. The cyclic carboxylate and lithium oxalate additives form thermally stable interface films that serve as protective barriers, allowing the battery to maintain performance at elevated temperatures without degrading the electrode material.
Solution Approach 2:
The patent applies beforehand cushioning by pre-forming protective interface films on the electrode surface through the electrolyte additives before thermal degradation can occur. These films act as cushioning layers that prevent direct thermal damage to the high-nickel electrode during high-temperature operation and storage.
3Reliability
If conventional electrolyte additives are used, then the interface film formation is achieved, but the film impedance is high and lithium ion conduction is slow
Solution Approach 1:
The patent creates a composite interface film through the synergistic combination of cyclic carboxylate additives and lithium oxalate in the electrolyte. This composite film structure combines the benefits of both components: the cyclic carboxylate provides structural stability while lithium oxalate contributes to low impedance and high ionic conductivity. The composite nature allows simultaneous achievement of stability and fast conduction.
Solution Approach 2:
The patent optimizes the concentration parameters of the electrolyte additives to achieve the desired film properties. By controlling the content of cyclic carboxylate (0.01-5%) and lithium oxalate (0.01-1%), the film composition and structure are tuned to achieve both high stability and low impedance, enabling fast lithium ion conduction while maintaining film integrity.
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 additives effectively inhibits oxidative decomposition, reduces impedance, and enhances the power and high-temperature storage performance of lithium-ion batteries by forming a stable interface film, thereby improving the overall performance and longevity of the batteries.
Implementation Method 1
the synergize action of the two additives can form a uniform, chemically stable and low-impedance interface film on the surfaces of the positive and negative electrodes
Implementation Method 2
the impedance of the interface film is low, so that lithium ions can be quickly conducted in the electrolyte itself
Implementation Method 3
suppress the expansion of the cell during high-temperature storage
Data Source
AI summary
The present disclosure provides an electrolyte and a lithium-ion battery. The electrolyte includes an electrolyte salt, an organic solvent and additives. The additives include a first additive that is one or more selected from compounds shown as Formula 1, and a second additive that is one or more selected from compounds shown as Formula 2. The first additive and the second additive act synergistically and can effectively reduce the DCR growth of a lithium-ion battery during use.