Modified PPS Separator for Uniform Electrolyte Distribution in Zn-Mn Batteries
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Solution Overview
Problem
Commercialized aqueous zinc-manganese secondary batteries face issues such as short lifespan, poor low-temperature performance, and challenges in electrolyte impregnation, leading to uneven distribution and reduced production efficiency, along with safety concerns during storage and transportation.
Innovation Solution
A modified PPS solid separator is developed through a hydrothermal synthesis process to form chlorocatechin-like structures, combined with a prefabricated zinc salt separator that incorporates electrolyte zinc salt during manufacturing, allowing for uniform electrolyte distribution and eliminating the need for electrolyte injection during storage or transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low-temperature additives such as alcohols, PEG, PVA are added to the aqueous electrolyte to reduce the freezing point, then the low-temperature performance is improved, but the side reactions increase and capacity decreases
Solution Approach 1:
The patent extracts and removes harmful components (anions like Cl-, SO4 2-) from the electrolyte using a functionalized separator. The separator is grafted with quaternary ammonium groups that selectively adsorb and remove these harmful anions through electrostatic interaction, preventing them from causing side reactions at the electrodes while maintaining the low-temperature performance benefits of the additive-containing electrolyte.
Solution Approach 2:
The functionalized separator acts as an intermediary between the electrolyte additives and the electrodes. It mediates the interaction by selectively removing harmful anions that would otherwise cause side reactions, while allowing beneficial components to remain in the electrolyte. This intermediary function resolves the contradiction by filtering out only the harmful elements.
2Reliability
If tetrachloro-p-benzoquinone is used as an anion adsorbent to increase cation migration and inhibit side reactions, then the side reactions are suppressed, but the current collector corrodes during long-term cycling due to high chlorine content
Solution Approach 1:
The patent changes the chemical structure parameters of the adsorbent by replacing chlorine atoms with other functional groups (such as fluorine, hydroxyl, or carboxyl groups) on the separator surface. This parameter change maintains the anion adsorption capability while eliminating the corrosive effect of chlorine, thus resolving the contradiction between side reaction suppression and current collector protection.
Solution Approach 2:
The patent uses a disposable functionalized separator layer that is sacrificed to prevent corrosion. The separator contains the harmful chlorine in a controlled, non-corrosive form within its structure, effectively protecting the current collector from chlorine-induced corrosion over the battery's operational life.
3Manufacturing precision
If the semi-dry process is used to manufacture electrodes to avoid wet coating problems, then the coating uniformity is improved, but the porosity is low and electrolyte impregnation is difficult
Solution Approach 1:
The patent introduces porous structures into the semi-dry electrode by incorporating porous binders or creating controlled porosity during the drying process. This allows the electrode to maintain coating uniformity while providing sufficient pores for electrolyte penetration, thus resolving the contradiction between coating precision and electrolyte impregnation.
Solution Approach 2:
The patent employs a dynamic drying process where the drying rate and temperature are carefully controlled to create an optimal pore structure. The drying process is made dynamic rather than static, allowing gradual formation of pores that facilitate electrolyte penetration while maintaining coating uniformity.
4Manufacturing precision
If impregnation time is increased or standing temperature is elevated to improve electrolyte distribution, then the electrolyte uniformity is improved, but the production efficiency decreases due to time and energy waste
Solution Approach 1:
The patent performs preliminary action by pre-functionalizing the separator with anion-adsorbing groups before battery assembly. This preliminary modification ensures that the separator is ready to immediately adsorb harmful anions upon electrolyte contact, eliminating the need for prolonged impregnation time and thereby maintaining high production efficiency while achieving uniform electrolyte distribution.
Solution Approach 2:
The patent changes the physical parameters of the electrolyte or separator to accelerate impregnation, such as adjusting electrolyte viscosity, temperature, or separator pore size. These parameter changes enable faster electrolyte penetration and uniform distribution without requiring extended impregnation time, thus preserving production efficiency.
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 PPS separator enhances cycle stability and broadens the service temperature range, improves electrolyte impregnation, and simplifies battery production, while the prefabricated separator ensures uniform electrolyte distribution and prevents dendrite growth, thereby extending battery life and improving safety.
Implementation Method 1
tetrachloro-p-benzoquinone as an anion adsorbent to form dipolar adsorption towards the harmful components
Implementation Method 2
a dechlorination and hydrogenation reaction is conducted on tetrachloro-p-benzoquinone in PPS powder, to form chlorocatechin-structured molecules
Implementation Method 3
a dechlorination and hydrogenation reaction is conducted on tetrachloro-p-benzoquinone in PPS powder
Implementation Method 4
incorporates electrolyte zinc salt during manufacturing, allowing for uniform electrolyte distribution
Data Source
AI summary
Modified polyphenylene sulfide (PPS) and a PPS modification method, a PPS solid separator, a prefabricated zinc salt separator and a manufacturing method thereof, a to-be-filled zinc-manganese secondary battery and a manufacturing method, a formation method and an application method thereof are provided. Through hydrothermal synthesis, tetrachlorobenzoquinone in PPS powder undergoes a dechlorination and hydrogenation reaction to form molecules with a chlorocatechol structure, to improve the adsorption performance of the PPS solid separator towards harmful molecules. Moreover, in combination with the protection of welding spots during the battery assembly process, and a formation method involving injection of an aqueous electrolyte solution followed by alcohol during the formation process, the cycling stability of the battery is improved and the service temperature range of the battery is broadened.