Battery Electrolyte Additive for Stable SEI and Lower Cathode Resistance
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining high life-span and output characteristics, particularly in forming a stable solid electrolyte interface (SEI) film and reducing cathode interface resistance, which affects their capacity retention and charging/discharging efficiency.
Innovation Solution
A novel compound represented by Formula 1 is introduced, which is incorporated into the electrolyte of lithium secondary batteries, allowing for improved life-span and output characteristics by forming a stable SEI film and reducing cathode resistance. This compound is synthesized through reacting a sulfonate-based salt or sulfate-based salt with an alkali metal phosphate-based salt, and is used in combination with auxiliary additives to enhance the battery's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in lithium secondary batteries, then the basic charging and discharging function is achieved, but the life-span characteristics and capacity retention rate deteriorate due to unstable SEI film formation
Solution Approach 1:
The patent introduces a novel compound with specific molecular structure parameters (Formula 1 with specific R1-R5 substituents) to change the chemical composition parameters of the electrolyte. This parameter change enables the formation of a stable SEI film, directly resolving the contradiction between reliability improvement and SEI film stability.
Solution Approach 2:
The patent employs a composite electrolyte system combining the novel compound (Formula 1) with auxiliary additives and conventional electrolyte components. This composite approach creates a synergistic effect where the novel compound forms a stable SEI film while auxiliary additives enhance specific properties, simultaneously improving life-span characteristics and SEI film stability.
2Power
If conventional electrolytes are used in lithium secondary batteries, then the basic operation is maintained, but the output characteristics and charging/discharging efficiency deteriorate due to high cathode interface resistance
Solution Approach 1:
The novel compound (Formula 1) changes the interfacial resistance parameter at the cathode by introducing specific functional groups and molecular structures. This parameter change reduces cathode interface resistance, thereby improving both output characteristics and charging/discharging efficiency simultaneously.
Solution Approach 2:
The novel compound acts as an intermediary substance between the cathode and the electrolyte, facilitating better interfacial contact and ion transfer. This intermediary role reduces interface resistance and improves power characteristics without compromising charging/discharging efficiency.
3Power
If the electrolyte composition is varied to improve output characteristics by enhancing lithium ion conductivity, then the power and charging speed improve, but the life-span characteristics may deteriorate due to insufficient SEI film formation
Solution Approach 1:
The patent optimizes the concentration parameter of the novel compound in the electrolyte to achieve a balance between lithium ion conductivity and SEI film formation. By carefully controlling this parameter, the electrolyte maintains high ion conductivity for improved power while simultaneously forming a stable SEI film for enhanced life-span characteristics.
Solution Approach 2:
The composite electrolyte formulation combines the novel compound with auxiliary additives that have complementary functions. Some components enhance lithium ion conductivity for improved power output, while others promote stable SEI film formation for extended life-span, resolving the contradiction between these two performance aspects.
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 novel compound improves the capacity retention rate and output characteristics of lithium secondary batteries by forming a stable SEI film and reducing cathode interface resistance, leading to enhanced performance and extended battery life.
Implementation Method 1
the life-span characteristics of the lithium secondary battery may be improved by firmly forming a solid electrolyte interface (SEI) film on the anode
Implementation Method 2
a process of intercalating and deintercalating lithium ions from lithium metal oxide particles and graphite is repeated, such that charging and discharging may be performed
Implementation Method 3
reducing cathode interface resistance, which affects their capacity retention and charging/discharging efficiency
Data Source
AI summary
A compound according to an embodiment is represented by Formula 1. An electrolyte includes a lithium salt, an organic solvent, and the compound. A lithium secondary battery includes a cathode, an anode disposed to face the cathode, a separation membrane interposed between the cathode and the anode, and the electrolyte. In a method for preparing the compound, a compound represented by Formula 2 and a compound represented by Formula 3 are reacted.