Lithium-Ion Battery Electrolyte for Wettability and Heat Stability
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Solution Overview
Problem
Cylindrical lithium ion batteries face challenges in achieving high wettability and high temperature stability due to the use of dimethyl carbonate, which has poor stability and leads to side reactions, especially in high-nickel ternary and silicon-based electrode materials.
Innovation Solution
An electrolyte composition comprising 8% to 24% cyclic carbonate, 0.3% to 0.8% unsaturated inorganic additive, and optimized lithium salts like LiPF6 and LiFSI, which forms stable SEI and CEI films to inhibit side reactions and enhance wettability and high temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high content of dimethyl carbonate is used to improve wettability, then wettability is improved, but stability deteriorates causing side reactions and poor high temperature performance
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by replacing dimethyl carbonate with cyclic carbonate (specifically fluoroethylene carbonate) and adding unsaturated inorganic additive. This parameter change resolves the contradiction by achieving both high wettability and high stability simultaneously, eliminating the need to trade off between these two properties.
Solution Approach 2:
The patent creates a composite electrolyte system by combining cyclic carbonate (providing wettability) with unsaturated inorganic additive (providing stability through film formation). This composite approach allows the electrolyte to achieve both high wettability and high temperature stability, resolving the technical contradiction between these two properties.
2Quantity of substance
If high-nickel ternary and silicon-based electrode materials are used to improve energy density, then energy density is improved, but side reactions increase due to poor electrolyte stability
Solution Approach 1:
The unsaturated inorganic additive acts as an intermediary that forms protective films (SEI and CEI) on the electrode surfaces. This intermediary layer prevents direct contact between the electrolyte and high-nickel ternary/silicon-based electrode materials, thereby eliminating side reactions while allowing the high energy density materials to function properly.
Solution Approach 2:
The patent changes the electrolyte composition parameters by introducing unsaturated inorganic additive and cyclic carbonate, which fundamentally alters the electrochemical behavior at the electrode interface. This parameter change enables the use of high-nickel ternary and silicon-based materials by suppressing side reactions through improved film stability.
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 achieves simultaneous high wettability and high temperature stability, supporting fast charging and extended cycling performance in large-sized cylindrical batteries.
Implementation Method 1
the additive containing unsaturated bonds has higher reaction activity and may preferentially undergo a reaction on the electrode material to form a stable solid electrolyte interphase (SEI) film and cathode-electrolyte interphase (CEI) film
Implementation Method 2
the additive containing unsaturated bonds has higher reaction activity and may preferentially undergo a reaction on the electrode material
Data Source
AI summary
Provided are an electrolyte for lithium ion battery and a lithium ion battery, specifically relating to the field of electrolyte technology. The electrolyte includes an organic solvent, a lithium salt, and an additive. The organic solvent includes cyclic carbonate. A content of the cyclic carbonate in the electrolyte is 8% to 24%. The additive includes an unsaturated inorganic additive. A content of the unsaturated inorganic additive in the electrolyte is 0.3% to 0.8%. Through optimizing composition of the electrolyte solvent and introducing the unsaturated inorganic additive, high temperature performance of the battery is improved while wettability of the electrolyte is improved.