Cyano Silane Electrolyte for High-Voltage Lithium Battery Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face performance degradation due to the dissolution of transition metal ions from the positive electrode during high-voltage operation, leading to accelerated degradation and reduced capacity, especially under high-voltage and high-temperature conditions.
Innovation Solution
An electrolyte comprising a lithium salt, an organic solvent, and a cyano silane-based compound is used to minimize the oxidation decomposition reaction on the positive electrode surface, thereby suppressing the dissolution of transition metal ions. The cyano silane-based compound, with multiple cyano groups, forms strong bonds with transition metals, reducing side reactions and enhancing the stability of the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the lithium secondary battery is operated at a high voltage to achieve high energy density, then the energy density is improved, but the positive electrode undergoes oxidation decomposition reaction leading to transition metal ion dissolution and performance degradation
Solution Approach 1:
The patent introduces a specific electrolyte additive (compound with formula (1) or (2)) as an intermediary substance that mediates between the high-voltage operation and the positive electrode. This additive preferentially undergoes oxidation at the positive electrode surface, forming a protective film that prevents direct contact between the electrode and electrolyte, thereby suppressing transition metal ion dissolution while allowing high-voltage operation to maintain energy density.
Solution Approach 2:
The electrolyte additive performs preliminary protective action by forming a stable surface film on the positive electrode before significant oxidation decomposition can occur. This pre-formed protective layer prevents the harmful oxidation decomposition reaction and transition metal ion dissolution that would otherwise occur during high-voltage charging, thus maintaining performance stability while enabling high energy density operation.
2Productivity
If the lithium secondary battery is operated at high voltage and high temperature, then the charging speed and energy density are improved, but the oxidation decomposition reaction accelerates causing faster dissolution of transition metal ions
Solution Approach 1:
The electrolyte additive acts as a thermal and oxidative buffer, mediating the harsh high-temperature high-voltage conditions. The additive's molecular structure is designed to be more resistant to thermal degradation and oxidation than the electrode materials, forming a thermally stable protective film that prevents accelerated dissolution even under high-temperature fast charging conditions, thus extending battery life while maintaining high productivity.
Solution Approach 2:
The patent modifies the electrolyte composition by introducing compounds with specific molecular structures (formula (1) or (2)) that have higher oxidation potentials and thermal stability. This parameter change in the electrolyte system allows the battery to withstand higher temperatures and voltages without accelerating decomposition reactions, enabling fast charging while preserving battery longevity.
3Use of energy by moving object
If conventional electrolytes are used to enable high-voltage operation, then the energy density is improved, but the oxidation decomposition reaction causes transition metal ion dissolution and dendrite formation
Solution Approach 1:
The electrolyte additive serves as a protective intermediary that sacrificially oxidizes instead of the positive electrode materials. By having a lower oxidation potential than the electrode active materials, the additive forms a stable surface coating that blocks direct oxidation of the electrode, preventing transition metal ion dissolution and subsequent dendrite formation on the negative electrode, thus enabling high energy density operation without these harmful effects.
Solution Approach 2:
The patent converts the harmful oxidation reaction into a beneficial protective mechanism. Instead of allowing direct oxidation of the positive electrode that causes metal ion dissolution, the electrolyte additive undergoes controlled oxidation to form a stable protective film. This transforms the harmful oxidative environment into a beneficial protective layer that prevents further degradation, enabling high energy density operation without the adverse effects.
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 effectively improves the capacity and safety of lithium secondary batteries by reducing the dissolution of transition metal ions, maintaining energy density and extending the battery's life even under high-voltage and high-temperature conditions.
Implementation Method 1
the cyano silane-based compound, with multiple cyano groups, forms strong bonds with transition metals, reducing side reactions
Implementation Method 2
electricity is generated or consumed by oxidation and reduction reactions caused by the intercalation and deintercalation of the lithium ions
Implementation Method 3
since a surface of the positive electrode is damaged by an oxidation decomposition reaction of the positive electrode at a high voltage
Data Source
AI summary
An electrolyte for a lithium secondary battery and a lithium secondary battery including the same are disclosed herein. In some embodiments, an electrolyte includes a lithium salt, an organic solvent, and at least one cyano silane-based compound selected from the group consisting of compounds represented by Formulae 1 to 3.