Plasma-Treated Separator Surface Energy for Battery Wettability
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Solution Overview
Problem
Conventional separators for rechargeable lithium batteries have inadequate wettability with electrolytes, leading to suboptimal lithium ion mobility and battery performance, particularly in terms of capacity and cycle-life characteristics.
Innovation Solution
A separator with a surface energy of 45 mN to 50 mN/m, featuring oxygen-containing functional groups such as ketone or ester groups, is fabricated using plasma treatment on polymer films like polyethylene or polyvinylidene fluoride, enhancing its wettability and impregnation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional separator is used, then the battery structure is simple, but the wettability with electrolyte is insufficient leading to poor lithium ion mobility
Solution Approach 1:
The patent applies plasma treatment to modify the surface energy and chemical composition of the separator, changing parameters such as surface oxygen-containing functional groups and contact angle to achieve optimal wettability (45-50 mN/m surface energy) for enhanced electrolyte impregnation and lithium ion mobility
Solution Approach 2:
The separator undergoes preliminary plasma treatment during manufacturing to pre-establish the optimal surface properties before battery assembly, ensuring that the separator is ready to provide excellent wettability and lithium ion mobility from the start of battery operation
2Ease of operation
If the separator surface energy is increased to improve wettability, then electrolyte impregnation is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent replaces complex multi-step chemical treatments with a single plasma treatment process that achieves the desired surface energy modification through physical plasma exposure, simplifying the manufacturing process while achieving excellent electrolyte impregnation
Solution Approach 2:
The patent optimizes plasma treatment parameters (power, time, gas composition) to achieve the target surface energy range of 45-50 mN/m, balancing the need for excellent wettability with reasonable manufacturing complexity by establishing standardized process parameters
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 modified separator improves lithium ion mobility and battery performance by ensuring uniform and fast electrolyte impregnation, resulting in enhanced capacity and cycle-life characteristics of rechargeable lithium batteries.
Implementation Method 1
The separator may be fabricated by radiating plasma under a current of from about 1800 mA to about 2000 mA and electric power of from about 2750 W to about 3000 W on a polymer film
Implementation Method 2
a separator for rechargeable lithium battery having surface energy of about 45 mN to about 50 mN/m... having excellent wettability for an electrolyte
Data Source
AI summary
Disclosed is a separator having surface energy of about 45 mN to about 50 mN/m which can be prepared by radiating plasma on a polymer film under a current of from about 1800 mA to about 2000 mA and electric power of from about 2750 W to about 3000 W. Further disclosed is a rechargeable battery comprising the separator having a surface energy of about 45 mN to about 50 mN/m.