Single-ion polymer electrolyte membrane based on sulfonated graphene oxide as well as preparation method and application thereof

An electrolyte separator and polymer technology, applied in the field of electrochemistry, can solve problems such as unfavorable electrolyte adsorption and retention, explosion, and increase in lithium salt concentration gradient, and achieve excellent thermal dimensional stability, improved safety performance, and good rate performance. Effect

CN111029515AActive Publication Date: 2020-04-17CHINA UNIV OF GEOSCIENCES (WUHAN)
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-04-17

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Abstract

The invention discloses a single-ion polymer electrolyte membrane based on sulfonated graphene oxide as well as a preparation method and application thereof and belongs to the technical field of electrochemistry. The membrane disclosed by the invention has uniform and compact pore structure distribution, the porosity is 55-57%, the liquid absorption rate of the diaphragm is 138-141%, and pores arecommunicated with one another in the membrane, so that the establishment of a lithium ion transmission channel is facilitated. According to the invention, the sulfonated graphene oxide is doped intoa single-ion polymer electrolyte taking wholly aromatic polyamide as a framework support by adopting an in-situ polymerization method, so that the ionic conductivity of the electrolyte can be improved. The membrane disclosed by the invention is applied to a LiFePO4 half-cell, and the membrane shows good rate capability at room temperature: the specific discharge capacity at 0.1 C rate reaches 143mAh.G<-1>, the specific discharge capacity is hardly attenuated after 60 circles of charging and discharging at 1C, and the electrochemical performance is excellent.
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Description

technical field

[0001] The invention belongs to the technical field of electrochemistry, and in particular relates to a single-ion polymer electrolyte diaphragm based on sulfonated graphene oxide and its preparation method and application. Background technique

[0002] At present, the commercial polymer electrolyte is composed of microporous polyolefin separator / liquid electrolyte system, but the system still has the following major disadvantages: (1) The low glass transition temperature and low melting point of polyolefin make the system Under high temperature conditions, the shrinkage is severe. Once the temperature is too high, it will cause a short circuit inside the battery, resulting in fire or even explosion; (2) The pore structure of the polyolefin separator is produced by the stretching process. In order to ensure the high mechanical strength of the separator, the porosity is usually If it is less than 50%, it is not conducive to the adsorption and retention of the ...

Examples

preparation example Construction

[0064] (i) Preparation of cathode material

[0065] The positive electrode material used in the present invention is lithium iron phosphate positive electrode, and active material LiFePO 4 , the mixture of conductive agent acetylene black and binder PVDF was uniformly dissolved in NMP, uniformly mixed with a mass ratio of 7:2:1, and stirred for 12 hours, during which ultrasonic treatment was performed three times, each time for 20 minutes, to obtain a yogurt-like viscous slurry, The slurry was then poured onto a flat aluminum foil and spread evenly with a spatula. After the solvent was fully volatilized, it was cut into discs with a diameter of 15 mm by a punching machine, and vacuum-dried at 60° C. for 24 h to be used in button cells.

[0066] (ii) Assembly of button cell

[0067] Adopt CR2025 type button battery to test among the present invention, take lithium iron phosphate as positive electrode material, the prepared single-ion polymer electrolyte membrane is diaphragm,...

Embodiment 1

[0071] A method for preparing a single-ion polymer electrolyte membrane based on sulfonated graphene oxide of the present embodiment, the method specifically includes the following steps:

[0072] (1) Synthesis of precursor bis(4-carbonylbenzenesulfonyl)imide (CBSI)

[0073](a) The specific synthesis process of the precursor bis(4-carbonylbenzenesulfonyl)imide (CBSI) is shown in Formula 1. Take 0.1145mol of p-toluenesulfonamide, 0.1202mol of lithium hydroxide, and 0.0573mol of water in a 250mL two-necked bottle, heat to 95°C until they are completely dissolved, then slowly add 0.0573mol of p-toluenesulfonyl chloride for about 2 hours, and let stand overnight. When the reaction temperature drops to 45°C, adjust the pH to 7.0 with 1mol / L HCl, let it stand overnight, filter, the filter cake is p-toluenesulfonamide, store it dry, add the filtrate dropwise with concentrated hydrochloric acid until no precipitation occurs, filter, and filter The cake was recrystallized with a larg...