Electrode Passivation Layer for Aqueous Battery Safety
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Solution Overview
Problem
Lithium-ion batteries face safety concerns due to flammable organic solvents, leading to thermal runaway and catastrophic failures, limiting their use in flexible and lightweight applications that require high energy density without sacrificing safety.
Innovation Solution
The development of electrodes with a passivation layer comprising a cured propoxylated polymer and an uncured hydrophobic glycol ether, which inhibits water migration and suppresses electrochemical activity, allowing for the use of aqueous-based electrolytes that reduce the risk of thermal runaways and enhance energy density and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If organic solvents are used in lithium-ion batteries to achieve high energy density, then energy density is improved, but safety deteriorates due to flammability and thermal runaway risk
Solution Approach 1:
A passivation layer comprising a cured propoxylated polymer and uncured hydrophobic glycol ether is introduced as an intermediary between the electrode and the aqueous-based electrolyte. This passivation layer prevents direct contact and harmful interactions while allowing ionic transport, thereby enabling the use of safer aqueous electrolytes without sacrificing energy density
Solution Approach 2:
The invention changes the chemical composition and physical state parameters of the electrolyte system by using a non-aqueous passivation layer in combination with aqueous-based electrolyte. The passivation layer's hydrophobic character and cured polymer matrix create a stable interface that enables high energy density operation with intrinsically safer aqueous electrolytes
2Reliability
If aqueous-based electrolytes are used to improve safety, then safety is improved, but energy density deteriorates compared to organic solvent systems
Solution Approach 1:
The passivation layer acts as a mediator that overcomes the limitations of aqueous electrolytes by providing a stable interface that enables higher operating voltages and energy densities while maintaining the safety benefits of non-flammable aqueous-based electrolyte composition
Solution Approach 2:
The passivation layer is formed as a composite material combining cured propoxylated polymer and uncured hydrophobic glycol ether, creating a multi-phase structure that optimizes both ionic conductivity and electrochemical stability, thereby enabling high energy density with aqueous-based electrolytes
3Reliability
If a passivation layer is formed on the electrode to enable aqueous electrolyte use, then safety and energy density are improved, but device complexity increases due to additional manufacturing steps
Solution Approach 1:
The passivation layer is formed on the electrode surface before assembly into the battery cell. This preliminary action simplifies the overall manufacturing process by preparing the electrode in advance, allowing for modular assembly and reducing the complexity of integrating the passivation function into the final battery manufacturing line
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 passivation layer significantly improves battery safety and performance by reducing water decomposition and enhancing coulombic efficiency, enabling flexible and lightweight batteries with improved energy density and cycle life.
Implementation Method 1
The passivation layer may comprise: (i) a matrix material comprising (a) a cured propoxylated polymer, (b) an uncured hydrophobic glycol ether, or a combination of (a) and (b)
Data Source
AI summary
Electrodes including a passivation layer formed prior to receiving an initial charge are provided. The electrodes comprise an electrode-composition including an active electrode species, in which the electrode-composition comprises a first surface. The electrodes also comprise a passivation layer positioned onto at least a portion of the first surface. The passivation layer comprises: (i) a matrix material comprising (a) a cured propoxylated polymer, (b) an uncured hydrophobic glycol ether, or a combination of (a) and (b); and (ii) at least a first electrolyte. The electrodes may be included into an electrochemical cell.