Lactide Additive for SEI Film Formation in Lithium Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face degradation in cycle life and high-temperature storage characteristics due to electrolyte decomposition and weak solid electrolyte interface (SEI) films, leading to reduced capacity and safety concerns.
Innovation Solution
A lactide-like compound with only one non-hydrogen substituent is used as an additive in the non-aqueous electrolyte, forming a firm and dense SEI film with improved chemical and thermal stability, reducing irreversible capacity and preventing electrolyte decomposition under high-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional electrolyte compositions are used to achieve high drive voltage (0-4.2V), then battery capacity density is improved, but electrolyte decomposition occurs on electrode surfaces leading to poor cycle life and high-temperature storage characteristics
Solution Approach 1:
The lactide compound performs preliminary action by forming a stable SEI film on the anode surface before the main electrolyte can decompose. This preliminary protective layer prevents subsequent electrolyte decomposition during charge/discharge cycles, thereby improving cycle life while maintaining high capacity density
Solution Approach 2:
The lactide compound acts as an intermediary substance between the anode and the main electrolyte. It mediates the interaction by forming a protective interface layer that prevents direct contact and harmful reactions between the electrolyte and anode, thus improving reliability without sacrificing capacity
2Quantity of substance
If conventional electrolyte compositions are used to achieve high drive voltage, then battery capacity density is improved, but high-temperature storage characteristics deteriorate due to electrolyte decomposition
Solution Approach 1:
The lactide compound performs preliminary protection by forming a thermally stable SEI film before high-temperature storage conditions can cause electrolyte decomposition. This preliminary action creates a barrier that prevents thermal degradation of the electrolyte during storage
Solution Approach 2:
The lactide compound serves as a thermal intermediary layer between the anode and electrolyte. It mediates thermal stress by absorbing and distributing heat, preventing direct thermal decomposition of the electrolyte during high-temperature storage while maintaining battery capacity
3Reliability
If electrolyte decomposition is prevented to improve cycle life, then reliability is improved, but charge/discharge efficiency may be reduced
Solution Approach 1:
The invention changes the chemical parameters of the electrolyte system by introducing the lactide compound with specific molecular structure and properties. This parameter change allows the formation of an SEI film with optimal characteristics that provides both protection (improving cycle life) and maintains ion conductivity (preserving charge/discharge efficiency)
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 compound enhances initial charge/discharge efficiency, extends cycle life, and maintains battery quality under high-temperature storage, inhibiting side reactions and swelling, thus improving the overall performance and safety of lithium secondary batteries.
Implementation Method 1
the compound represented by Formula 1, into which only one non-hydrogen substituent is introduced, as one of the constitutional elements forming a non-aqueous electrolyte for a battery
Implementation Method 2
improving the quality of a battery by using an additive for non-aqueous electrolytes
Data Source
AI summary
Disclosed is an electrolyte for a battery, which comprises: (a) an electrolyte salt; (b) a solvent for electrolyte; and (c) a compound represented by the following formula 1:wherein R is a halogen atom, or a halogen-substituted or non-substituted C1˜C10 alkyl group or alkenyl group. An electrode comprising a passivation layer partially or totally formed on a surface thereof, wherein the passivation layer comprises a compound represented by the following Formula 1 or a chemical reaction product thereof, and a secondary battery using the electrolyte and/or the electrode are also disclosed. The compound can improve the initial charge/discharge efficiency and cycle life characteristics of a secondary battery, and can inhibit a battery from swelling under high-temperature storage conditions.