Polyethylene Glycol Polymer Electrolyte for Lithium Battery Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries with high nickel-based cathode active materials face issues of swelling, explosion, and reduced lifespan due to gas generation, especially in high temperature environments, caused by the chemical instability and reaction with electrolytes.
Innovation Solution
Incorporating a polyethylene glycol-based polymer in the nonaqueous electrolyte to suppress carbon dioxide generation by filling cracks in the lithium transition metal oxide particles and reducing excessive contact with the electrolyte, thereby stabilizing the battery and extending its lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high nickel-based cathode active material is used to achieve high energy density, then the energy density is improved, but the battery exhibits swelling, explosion, and reduced lifespan due to gas generation in high temperature environments
Solution Approach 1:
A coating layer comprising at least one of a metal oxide and a metal hydroxide is applied to the surface of the nickel-based cathode active material particles. This coating layer acts as an intermediary barrier between the high nickel-based cathode material and the electrolyte, preventing direct contact and chemical reactions that generate gas. The coating layer specifically suppresses carbon dioxide generation by blocking the interaction between the unstable nickel-based material and water-containing electrolytes, thereby preventing swelling and explosion while maintaining high energy density
Solution Approach 2:
The cathode active material is designed as a composite structure where a coating layer (metal oxide or metal hydroxide) is combined with the high nickel-based cathode active material core. This composite structure integrates the high energy density advantage of nickel-based materials with the stability and protective properties of the coating layer, resolving the contradiction between energy density and reliability
2Use of energy by moving object
If the nickel content in the cathode active material is increased to achieve high energy density, then the energy density is improved, but the chemical stability deteriorates leading to gas generation
Solution Approach 1:
The coating layer serves as a protective intermediary that isolates the chemically unstable high nickel-based cathode material from the electrolyte environment. This prevents water-containing electrolytes from contacting the nickel-based material and generating carbon dioxide gas through chemical reactions, thereby maintaining chemical stability while preserving the high energy density properties
Solution Approach 2:
The surface properties of the cathode active material are modified by applying a coating layer with different chemical composition and properties. This parameter change at the surface level protects the bulk high nickel-based material from chemical degradation and gas-generating reactions with the electrolyte, maintaining both high nickel content and chemical 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 use of polyethylene glycol-based polymer significantly decreases carbon dioxide generation, preventing battery swelling and explosion, and enhances the battery's stability and lifespan by reducing gas-related stress and chemical instability.
Implementation Method 1
the polyethylene glycol-based polymer is present in the crack
Data Source
AI summary
Provided is a lithium secondary battery including: a cathode including a cathode current collector and a cathode active material layer positioned on the cathode current collector; a nonaqueous electrolyte; and an anode, wherein the cathode active material layer includes a lithium transition metal oxide particle, and the lithium transition metal oxide particle contains a nickel (Ni) atom in an amount of 60 mol% or more with respect to a total of 100 mol% of transition metal atoms, and the nonaqueous electrolyte contains a polyethylene glycol-based polymer.