Lithium Battery Separator with Porous Carbon Coating
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Solution Overview
Problem
Lithium-sulfur and lithium-ion batteries face issues such as limited life cycles due to the poor conductivity of sulfur, shuttling of lithium-polysulfide intermediates, and poisoning of electrodes by transition metal cations, leading to decreased performance and durability.
Innovation Solution
A lithium-based battery separator featuring a porous polymer membrane with a porous carbon coating and incorporated polycations, which absorbs or repels lithium-polysulfide intermediates and transition metal cations, preventing their migration and enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a porous polymer membrane is used as a battery separator, then ion transport is enabled, but lithium-polysulfide intermediates can migrate through the membrane causing the shuttle effect
Solution Approach 1:
The patent employs a porous carbon coating layer on the separator membrane. The porous structure allows lithium ions to transport through while the carbon material provides adsorption sites for lithium-polysulfide intermediates, preventing their migration and mitigating the shuttle effect.
Solution Approach 2:
The separator is designed as a composite structure combining porous polymer membrane with porous carbon coating. This composite approach enables the separator to simultaneously provide ion transport pathways and adsorb harmful lithium-polysulfide intermediates, resolving the contradiction between productivity and harmful factors.
2Power
If transition metal cations are present in the battery, then electrochemical reactions occur, but they poison the electrodes leading to decreased durability
Solution Approach 1:
The porous carbon coating acts as an intermediary layer between the electrodes and the electrolyte containing transition metal cations. It allows necessary electrochemical reactions to occur while blocking or adsorbing the toxic cations, preventing electrode poisoning and maintaining long-term durability.
Solution Approach 2:
The porous carbon structure provides a physical barrier and adsorption capacity that selectively interacts with transition metal cations, enabling the separator to protect electrodes from poisoning while maintaining battery power output.
3Use of energy by moving object
If sulfur is used as the cathode material, then high energy density is achieved, but poor conductivity limits battery performance
Solution Approach 1:
The separator uses a composite of porous polymer and porous carbon materials. The carbon component provides electrical conductivity pathways while the porous polymer maintains the structural integrity and porosity necessary for ion transport, thereby supporting both high energy density and reliable conductivity.
Solution Approach 2:
The porous carbon coating provides conductive pathways that enhance the overall electrical conductivity of the separator system, enabling better performance utilization of the high-energy-density sulfur cathode material.
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 solution significantly improves sulfur utilization, cycleability, and overall performance of lithium-sulfur batteries, while also enhancing the durability and cycleability of lithium-ion batteries by mitigating the shuttle effect and electrode poisoning.
Implementation Method 1
A porous carbon coating is formed on one of the opposed surfaces of the porous polymer membrane. Polycations are incorporated in the porous carbon coating, in the porous polymer membrane, or in both the porous carbon coating and the porous polymer membrane.
Implementation Method 2
Polycations are incorporated in the porous carbon coating, in the porous polymer membrane, or in both the porous carbon coating and the porous polymer membrane.
Data Source
AI summary
A lithium-based battery separator includes a porous polymer membrane having opposed surfaces. A porous carbon coating is formed on one of the opposed surfaces of the porous polymer membrane. Polycations are incorporated in the porous carbon coating, in the porous polymer membrane, or in both the porous carbon coating and the porous polymer membrane.