Lithium-Ion Battery Electrolyte Additives for High-Nickel Cathode Gas Control
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Solution Overview
Problem
High-nickel positive electrode materials in lithium ion secondary batteries face issues such as gas generation due to decomposition reactions, side reactions, and transition metal ion dissolution, leading to safety risks like battery swelling and explosion, with existing solutions failing to effectively address energy density, initial power, and safety concerns.
Innovation Solution
A lithium ion secondary battery electrolyte containing a non-aqueous solvent, lithium salt, and an additive with specific unsaturated functional groups that capture transition metal ions and neutralize H+ to prevent internal short circuits and gas generation, enhancing safety and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-nickel positive electrode materials are used to achieve high energy density, then energy density is improved, but gas generation occurs due to decomposition reactions and transition metal ion dissolution leading to safety risks
Solution Approach 1:
The patent introduces a specific additive compound as an intermediary substance between the high-nickel positive electrode material and the electrolyte. This additive contains heteroatoms (nitrogen, fluorine, or oxygen) that can complex with transition metal ions, preventing their dissolution and subsequent gas-generating side reactions. The additive acts as a mediator that allows the high-nickel material to function at high energy density while preventing the harmful gas generation through ion complexation.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by adding a specific compound with controlled concentration (0.01-5 wt%). This parameter change introduces new chemical functionality (ion complexation capability) to the electrolyte system, enabling it to prevent transition metal ion dissolution without compromising the high energy density performance of the high-nickel positive electrode material.
2Speed
If transition metal ions dissolve from the positive electrode, then ion mobility increases, but internal short circuits occur when these ions diffuse to the negative electrode
Solution Approach 1:
The additive compound serves as an intermediary that selectively binds to transition metal ions in the electrolyte through complexation reactions involving heteroatoms (nitrogen, fluorine, or oxygen). This binding prevents the ions from migrating to the negative electrode while maintaining overall ion mobility in the system, as the complexed ions remain in solution but are prevented from causing short circuits.
Solution Approach 2:
The patent effectively extracts or removes the harmful mobility of free transition metal ions by having them complexed with the additive compound. While the ions themselves remain in the electrolyte, their harmful diffusive mobility toward the negative electrode is taken out by forming stable complexes, thereby preventing internal short circuits while maintaining battery operation.
3Object-affected harmful factors
If conventional additives (material coating, film-forming additives, transition metal ion trapping agents, or stabilizers) are used to prevent gas generation, then gas generation is reduced, but energy density and initial power deteriorate
Solution Approach 1:
The patent changes the chemical parameter of the electrolyte by introducing a specific additive compound with heteroatoms capable of ion complexation. This parameter change provides a new mechanism for preventing gas generation (ion complexation) that does not interfere with the electrochemical performance, unlike conventional additives that form coatings or films that impede ion transport and reduce energy density and power.
Solution Approach 2:
The patent creates a composite electrolyte system by combining the base electrolyte with the specific additive compound. This composite approach integrates the ion complexation functionality of the additive with the electrochemical properties of the base electrolyte, achieving gas generation prevention while maintaining high energy density and initial power, unlike conventional single-function additives.
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 electrolyte prevents transition metal ion dissolution, improves initial kinetics, and reduces gas generation, thereby enhancing the safety and performance of lithium ion secondary batteries.
Implementation Method 1
the ability of nitrogen atoms with lone pair electrons is used to complex with empty d-orbitals of transition metal ions to capture potentially escaping transition metal ions
Implementation Method 2
H+ generated in the system is neutralized
Implementation Method 3
introduce unsaturated functional groups with a good lithium ion conduction ability on the positive electrode side
Data Source
AI summary
A lithium ion secondary battery electrolyte and an application thereof are provided. The electrolyte includes a non-aqueous solvent, a lithium salt, and an additive including a compound represented by any one of Formulas (I)-(III):where R1, R2, R3, R4, R5, R6, and R7 are each substituents with 1-3 carbon atoms, 0-3 heteroatoms, and unsaturation of 0-4, R8 is a cyclic substituent with unsaturation of 0-4, and with 0-5 heteroatoms, R9 is vinyl, allyl, butenyl, 1,3-butadienyl, ethynyl, propynyl when the unsaturation of R8 is 0, the R9 substituent does not exist when the unsaturation of R8 is 1-4, the heteroatoms are selected from at least one of nitrogen, fluorine, and oxygen, and n is 0-2. The lithium ion secondary battery electrolyte and the application may prevent the dissolution of transition metal ions on the positive electrode, improve initial kinetics and gas generation issues, and enhance performance.