High-Nickel Li-Ion Electrolyte Additive for Gas Suppression
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Solution Overview
Problem
Lithium-ion batteries, particularly high-nickel and high-voltage ternary batteries, face significant gas production issues during cycling due to the decomposition of alkaline compounds and structural instability of the positive electrode material, leading to poor high-temperature cycling performance.
Innovation Solution
Incorporating a non-aqueous electrolyte with a specific compound represented by formula A-D-B-E-C, which forms a protective film on the positive electrode surface, inhibiting decomposition and enhancing structural stability, thereby reducing gas generation and improving high-temperature cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the nickel content in the positive electrode material is increased to improve capacity, then the battery capacity increases, but gas production increases and high-temperature cycling performance deteriorates
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance that mediates between the high-nickel positive electrode material and the electrolyte. This compound decomposes first to form a protective film, preventing direct harmful interactions between the electrolyte and the high-nickel material, thus reducing gas production while maintaining high capacity
Solution Approach 2:
The patent converts the harmful effect of fluorinated cyclic carbonate compound decomposition into a beneficial protective film. The compound decomposes under electrochemical conditions to form a stable film that protects the positive electrode material, transforming what could be a source of gas production into a protective mechanism
2Quantity of substance
If the nickel content in the positive electrode material is increased to improve capacity, then the battery capacity increases, but the structural stability of the positive electrode material deteriorates
Solution Approach 1:
The fluorinated cyclic carbonate compound acts as a protective intermediary that forms a stable film on the positive electrode surface. This film stabilizes the structure of high-nickel materials during cycling, preventing structural collapse while allowing high capacity utilization
3Quantity of substance
If the upper limit voltage of the lithium-ion battery is increased to improve capacity, then the battery capacity increases, but the gas production increases and high-temperature cycling performance deteriorates
Solution Approach 1:
The patent applies preliminary action by having the fluorinated cyclic carbonate compound decompose and form a protective film before the harmful high-voltage electrochemical reactions occur. This pre-formed film prevents subsequent gas-generating reactions during high-voltage charging and high-temperature cycling
Solution Approach 2:
The fluorinated cyclic carbonate compound serves as a protective intermediary between the electrolyte and the positive electrode material during high-voltage operation, preventing direct harmful interactions that would otherwise generate gas
4Ease of manufacture
If a conventional electrolyte is used in high-nickel ternary batteries, then the electrolyte cost is low, but the high-temperature cycling performance is poor
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing fluorinated cyclic carbonate compounds with specific molecular structures and properties. These parameter changes (fluorination, cyclic carbonate structure) provide superior high-temperature stability and protective film formation compared to conventional electrolytes
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 compound significantly increases capacity retention and reduces gas production during high-temperature cycling, with optimal results achieved when the nickel content in the positive electrode active material is high and the compound is added in appropriate amounts, forming a stable and elastic protective film that maintains electrode integrity.
Implementation Method 1
the compound represented by formula 1 decomposes on the surface of the positive electrode to form a protective film
Implementation Method 2
form a protective film, which uniformly covers the surface of the positive electrode material
Implementation Method 3
the activity of nickel ions is high, and it is easier and faster for the electrolyte to oxidize and decompose on the surface of the positive electrode material with high nickel content
Data Source
AI summary
A lithium-ion battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The positive electrode includes a positive electrode material layer, the positive electrode material layer includes a positive electrode active material, and the positive electrode active material includes LiNixCoyMnzL(1-x-y-2)O2, where L is Al, Sr, Mg. Ti, Ca, Zr, Zn, Si, Cu, V or Fe, 0.5≤x≤1, 0≤y≤0.5, 0≤z≤0.5, 0≤x+y+z≤1, and an upper limit voltage of the lithium-ion battery is ≥4.2 V. The non-aqueous electrolyte includes a solvent, an electrolyte salt and a compound represented by formula 1: A-D-B-E-C, Formula 1. Based on a total mass of the non-aqueous electrolyte as 100%, the compound represented by the formula 1 is added in an amount of 0.01 to 5.0%.