Lithium Battery Electrolyte Additive for High-Temperature SEI Stability
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Solution Overview
Problem
Lithium secondary batteries face structural deformation and side reactions due to high-temperature environments, leading to reduced lifespan and increased internal resistance, particularly when using lithium metal oxide particles as cathode active materials.
Innovation Solution
An electrolyte solution comprising a lithium salt, organic solvent, and a specific compound represented by Chemical Formula 1, which forms a robust solid electrolyte interphase (SEI) on the electrode surface, suppressing solvent decomposition and side reactions, thereby enhancing the battery's lifespan and high-temperature storage properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal oxide particles are used as cathode active material, then high operational voltage and energy density are achieved, but structural deformation and side reactions occur during repeated charging and discharging
Solution Approach 1:
A coating layer comprising at least one of an oxide of a transition metal element, an oxide of a rare-earth element, or a composite oxide of the transition metal element and the rare-earth element is formed on the surface of the lithium metal oxide particles. This coating layer acts as an intermediary between the lithium metal oxide particles and the electrolyte solution, preventing direct contact and side reactions while maintaining structural stability during charging and discharging cycles
Solution Approach 2:
The patent specifies controlled composition parameters for the coating layer, including the types of metal elements (transition metals such as Mn, Ni, Co, Cu, Zn, Mo, W; rare-earth elements such as La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and their weight ratios relative to the lithium metal oxide particles (0.1-10 wt%). These parameter changes optimize the protective function while maintaining high energy density
2Productivity
If lithium secondary battery operates in high-temperature environment, then charging and discharging can be maintained, but expansion of battery and increase of internal resistance occur
Solution Approach 1:
The coating layer serves as a thermal barrier and protective intermediary that reduces the impact of high-temperature environments on the lithium metal oxide particles. It prevents excessive heat from causing structural deformation and side reactions with the electrolyte solution, thereby maintaining storage stability while allowing charging operations to proceed
Solution Approach 2:
The patent optimizes the coating layer composition and thickness parameters to provide thermal protection. The specific weight ratio (0.1-10 wt%) and composition (oxide of transition metal element, oxide of rare-earth element, or composite oxide) are designed to withstand high-temperature conditions without degrading, thus preventing battery expansion and internal resistance increase
3Reliability
If coating layer is applied to lithium metal oxide particles, then side reactions with electrolyte solution are suppressed, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise composition parameters for the coating layer to achieve effective protection with minimal processing complexity. The coating layer comprises oxides of specific metal elements (transition metals and rare-earth elements) in controlled weight ratios (0.1-10 wt% relative to lithium metal oxide particles). These parameter specifications enable standardized manufacturing processes while ensuring chemical stability
Solution Approach 2:
The coating layer may be formed as a composite oxide combining transition metal elements and rare-earth elements, which provides enhanced protective properties. This composite approach allows for effective side reaction suppression while maintaining relatively simple manufacturing processes through conventional ceramic coating techniques
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 solution improves the lithium secondary battery's lifespan and high-temperature storage properties by forming a stable SEI, reducing resistance and preventing decomposition, thus maintaining performance under challenging conditions.
Implementation Method 1
A lithium secondary battery according to example embodiments includes the electrolyte solution to have improved life-span and high-temperature storage properties
Data Source
AI summary
An electrolyte for a lithium secondary battery includes a lithium salt, an organic solvent, and a compound represented by a certain chemical formula. A lithium secondary battery includes a case, an electrode assembly including an anode and a cathode stacked repeatedly and alternately, and the electrolyte solution accommodated in the case together with the electrode assembly.