Silane Additive Electrolyte for High-Ni Battery Durability
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Solution Overview
Problem
Nonaqueous secondary batteries face challenges with long-term durability and energy density, particularly due to oxidative deterioration of the electrolyte solution at the positive electrode active material sites and insufficient protection of the negative electrode, leading to increased internal resistance and capacity reduction.
Innovation Solution
A nonaqueous electrolyte solution comprising specific compounds such as those represented by general formulas (1) to (18), including alkyl and aryl groups, and acid anhydrides like malonic anhydride, is used to inhibit oxidative deterioration and enhance the physical strength of the protective film on the positive electrode, while also improving solubility resistance and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the Ni content in the positive electrode active material is increased to improve energy density, then the energy density is improved, but the voltage decreases and deterioration progresses
Solution Approach 1:
A silane compound is introduced as an intermediary substance that forms a protective film between the high-Ni positive electrode active material and the electrolyte solution. This intermediary layer suppresses oxidative deterioration of the electrolyte solution by the active material, thereby maintaining battery voltage and durability while preserving high energy density
Solution Approach 2:
The patent uses a composite approach by combining the silane compound with specific electrolyte additives (sulfone compound and carbonyl compound) to create a multi-component protective system. This composite formulation enhances the stability of the protective film and provides synergistic effects in preventing electrolyte decomposition
2Reliability
If electrode protection additives are added to form SEI on the negative electrode to inhibit reductive decomposition, then the negative electrode protection is improved, but the additives are consumed by the positive electrode active material sites
Solution Approach 1:
The silane compound is applied preliminarily to the positive electrode active material surface to create a protective barrier before the electrolyte additives can be consumed. This preliminary action prevents the harmful oxidative sites on the positive electrode from consuming the negative electrode protection additives, ensuring long-term durability
Solution Approach 2:
The silane compound acts as an intermediary that blocks the interaction between the positive electrode active material and the electrolyte additives. By forming a protective film on the positive electrode, it prevents direct contact and consumption of the additives, allowing them to fulfill their protective function on the negative electrode
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 inhibits oxidative deterioration and enhances the durability and output performance of the battery across various temperature environments, maintaining low internal resistance and cycle stability.
Implementation Method 1
oxidative deterioration of the electrolyte solution at the positive electrode active material sites
Implementation Method 2
highly ionic conductive electrolyte solution
Implementation Method 3
inhibit the reductive decomposition of the nonaqueous solvent
Data Source
AI summary
Provided is a nonaqueous electrolytic solution containing a nonaqueous solvent, a lithium salt, and at least one compound selected from the group consisting of compounds represented by general formula (1): R1—(S)n—R2, general formula (2): X—Si(OR3)(3-m)R4m, general formula (3), general formula (4), and general formula (18): X—Si(OR3′OR3)(3-m)R4m.