Sulfonated Separator Coating for Manganese Ion Capture in Batteries
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Solution Overview
Problem
Electrochemical devices using lithium manganese-based cathode active materials face capacity degradation due to manganese ions eluting from the cathode and precipitating on the anode, leading to non-uniform films and capacity loss.
Innovation Solution
A separator for electrochemical devices is developed, comprising a porous polymer substrate with a porous coating layer containing inorganic particles with a sulfonic acid group, where hydrogen cations in the sulfonic acid group are substituted with lithium cations, enhancing manganese ion adsorption capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional separator is used in electrochemical devices with lithium manganese-based cathode active material, then the device can operate, but manganese ions elute from the cathode and precipitate on the anode causing capacity degradation
Solution Approach 1:
The patent introduces a coating layer containing inorganic particles with sulfonic acid groups as an intermediary between the cathode and anode. This coating layer captures manganese ions through ion exchange (HSO3- + Li+ → LiSO3-), preventing them from reaching the anode while maintaining lithium ion conductivity for normal battery operation.
Solution Approach 2:
The patent modifies the chemical properties of the separator by introducing sulfonic acid groups onto inorganic particles in the coating layer. This parameter change enables the separator to actively interact with manganese ions through ion exchange, transforming it from a passive barrier to an active capture medium that selectively retains lithium ions while blocking manganese ions.
2Quantity of substance
If nickel or cobalt are used in cathode active material to improve capacity, then the capacity increases, but the price increases and thermal stability decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the cathode active material by using lithium manganese-based materials instead of nickel or cobalt-containing materials. This parameter substitution maintains high capacity while improving thermal stability, as manganese-based materials inherently possess better thermal stability compared to nickel or cobalt analogs.
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 separator effectively adsorbs manganese ions eluted from the cathode, reducing their migration to the anode and thereby minimizing capacity degradation and improving the overall performance of the electrochemical device.
Implementation Method 1
the first inorganic particles comprise a sulfonic acid group on a surface of a metal oxide or a metal hydroxide, and at least a portion of the sulfonic acid group comprises hydrogen cations substituted with lithium cations
Implementation Method 2
a separator for adsorbing manganese ions eluted from a cathode
Data Source
AI summary
Disclosed is a separator for an electrochemical device containing a lithium manganese-based active material. The separator includes a porous polymer substrate, and a porous coating layer which is laminated on at least one surface of the porous polymer substrate and contains inorganic particles and a polymer binder. The inorganic particles have a sulfonic acid group introduced on the surface of a metal oxide or metal hydroxide, and at least a portion of the sulfonic acid group has hydrogen cations substituted with lithium cations.