Lithium-Rich Separator Coating for Low-Resistance Battery Cycling
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Solution Overview
Problem
Existing lithium-ion battery recycling methods are energy-intensive and costly, and discarded batteries pose environmental risks, while traditional separator materials do not adequately address the need for improved kinetic and cycle performance in secondary batteries.
Innovation Solution
A separator with a coating containing lithium-rich particles, where the average particle size of the lithium-rich particles to the coating thickness ratio is 1:(1-15), enhances porosity and active ion permeability, reduces internal resistance, and replenishes lithium ions during charge and discharge processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pyro/hydrometallurgical methods are used for battery recycling, then metal extraction is effective, but energy consumption is high and process complexity increases
Solution Approach 1:
The patent extracts and recovers lithium ions from spent battery cathode materials by using the separator as a lithium source. The separator is designed to release lithium ions during battery formation and cycling, thereby replenishing lithium loss in the cathode without requiring energy-intensive pyro/hydrometallurgical processing.
Solution Approach 2:
The separator performs dual functions: it acts as both a physical barrier between electrodes and a lithium reservoir that automatically releases lithium ions when needed. This self-service mechanism eliminates the need for external lithium replenishment processes and avoids high-energy recycling methods.
2Strength
If separator thickness is increased to improve mechanical strength, then safety improves, but ion permeability and kinetic performance deteriorate
Solution Approach 1:
The patent employs a composite separator structure combining a polyolefin base membrane with a ceramic coating layer. This composite design provides both mechanical strength from the base membrane and high ion permeability from the porous ceramic layer, resolving the contradiction between strength and permeability.
Solution Approach 2:
The separator incorporates a ceramic coating with controlled porosity (30-70%) that allows rapid lithium ion transport. The porous structure maintains mechanical integrity while providing efficient ion conduction pathways, thus improving kinetic performance without sacrificing strength.
3Duration of action of stationary object
If lithium-rich particles are added to the separator coating, then cycle performance improves through lithium replenishment, but manufacturing complexity increases
Solution Approach 1:
The patent controls the particle size of lithium-rich additives within a specific range (0.1-10 μm) and adjusts their content in the coating (1-50 wt%). These parameter optimizations ensure effective lithium replenishment while maintaining manufacturability through standard coating processes.
Solution Approach 2:
The lithium-rich particles are selectively incorporated into the ceramic coating layer rather than the entire separator structure. This localized approach concentrates the lithium replenishment function where it is most needed (at the electrolyte interface) while keeping the overall manufacturing process relatively simple.
4Duration of action of stationary object
If coating thickness is increased to provide more lithium reservoir capacity, then cycle performance improves, but internal resistance and manufacturing complexity increase
Solution Approach 1:
The patent applies a coating thickness that provides sufficient lithium reservoir capacity (1-50 μm) without excessive buildup. This partial action approach achieves the necessary lithium replenishment effect while avoiding the drawbacks of overly thick coatings, such as increased internal resistance and manufacturing difficulties.
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 improves kinetic performance by reducing internal resistance and enhances cycle performance by replenishing lithium ions, thereby extending the life and safety of secondary batteries.
Implementation Method 1
the lithium-rich particles may undergo oxidative decomposition or dissolution, and the vacancies generated by the decomposition increase the porosity of the separator
Data Source
AI summary
A separator and a preparation method therefor, an electrode assembly, a secondary battery, a battery module, a battery pack and an electrical apparatus are disclosed. The separator comprises: a first microporous base membrane, a second microporous base membrane, and a coating disposed between the first microporous base membrane and the second microporous base membrane, wherein the coating comprises lithium-rich particles, and the ratio of the average particle size Dv50 of the lithium-rich particles to the thickness of the coating is 1:(1-15).