Synthesis And Properties Of Nitroxide Radical Polymers With Ionic Side Groups

Since the 1960 s it was discovered,the stable nitroxide radical have a special stability,which have been widely used in many aspects such as radiation chemistry and spin labeling,especially in the field of electrode materials.As the most promising free radical polymer system today,2,2,6,6-tetramethylpiperidine-1-nitroxyl radical(TEMPO),its derivative poly(2,2,6,6-tetramethylpiperidine-4-methyl acrylate-1-nitroxyl radical)(PTMA)is characterized as a new class of cathode active materials for lithium batteries.Poly(2,2,6,6-tetramethylpiperidine-4-acrylamido-1-nitroxyl radical)(PTAm)having the same TEMPO structure also has certain advantages in electrode materials.The Li-ion battery electrode material is a typical representative of the secondary battery,which has the advantages of environmental protection,recyclability,and high use efficiency.Different free radical polymer structures have a large influence on their electrical conductivity.Therefore,this thesis uses the free radical polymerization method to synthesize the basic structure of the assembled lithium ion button cell by synthesizing free radical polymers with different structures.The free radical polymer PTMA with acyloxy group was synthesized by random copolymerization polymerization method,and its structure and properties were tested.The sodium anion salt styrene sulfonate(SSS)and cationic salt dimethyl diallylammonium chloride(DMDAAC)were copolymerized with 2,2,6,6-tetramethylpiperidinyl 4-methyl acrylate(TMPM).The synthesized copolymer with different ionic pendant groups was oxidized to obtain a free radical polymer poly(2,2,6,6-tetramethylpiperidine-4-methyl acrylate-1-nitroxyl radical-sodium styrene sulfonate)(PTMA-co-PSS)and poly(2,2,6,6-tetramethylpiperidine-4-methyl acrylate-1-nitroxyl radical-codimethyl diallylchloride ammonium)(PTMA-co-PDMDAAC).The structure and thermal propertie were analyzed by a series of characterization methods.Three kinds of free radical polymers were used as electrode materials for lithium ion batteries,and their related electrical properties were analyzed.4-acrylamide-2,2,6,6-tetramethylpiperidine(AATP)with amide group was synthesized by acryloyl chloride with 4-amino-2,2,6,6-tetramethylpiperidine The free radical polymer poly(4-acrylamide-2,2,6,6-tetramethylpiperidine)(PTAm)was prepared by using AATP as a polymerization monomer,and its structure and properties were tested.The anionic salt SSS and the cationic salt DMDAAC were copolymerized with AATP,respectively.The synthesized copolymer with different ionic side groups was oxidized to obtain a free radical polymer poly(4-acrylamide-2,2,6,6-tetramethylpiperidine-sodium styrene sulfonate)(PTAm-co-PSS)and poly(4-acrylamide-2,2,6,6-tetramethylpiperidine-dimethyl diallylchloride ammonium)(PTAm-co-PDMDAAC).The structure and thermal propertie were analyzed by a series of characterization methods.Three kinds of free radical polymers were used as electrode materials for lithium ion batteries,and their related electrical properties were analyzed.The results showed that the synthesized free radical polymers PTMA,PTMA-co-PSS and PTMA-co-PDMDAAC were carried out by NMR,IR,UV-Vis,gel permeation chromatography,electron paramagnetic resonance and X-ray photoelectron spectroscopy,the target product was determined to be synthesized;By SEM analysis,different ion salts were added to the free radical PTMA backbone.The microporous structure of the free radical polymer PTMA was filled in a lamellar shape,which accelerated the transfer of electrons;thermogravimetric analysis showed that the free radical polymer has good heat resistance and meets the general use temperature conditions;as a positive electrode material for lithium batteries,the free radical polymers PTMA,PTMA-co-PSS and PTMA-co-PDMDAAC,PDMDAAC is assembled into a CR2025 button battery.The battery capacity tester and electrochemical workstation are used for battery capacity and AC impedance test.Compared with the free radical polymer PTMA,the free radicals have different ion side groups.The electrical properties of the base polymers PTMA-co-PSS and PTMA-co-PDMDAAC are superior.The structure of AATP and free radical polymers PTAm,PTAm-co-PSS and PTAm-co-PDMDAAC were characterized by nuclear magnetic resonance spectroscopy,infrared spectroscopy,gel permeation chromatography,electron paramagnetic resonance and X-ray photoelectron spectroscopy.The target product was determined to be synthesized;by SEM analysis,different ionic salts were added to the free radical PTAm backbone,and the layered structure of the surface of the free radical polymer PTAm was bonded and formed into a block shape;thermogravimetric analysis shows that the free radical polymer has good heat resistance and meets the general use temperature conditions;the free radical polymers PTAm,PTAm-co-PSS and PTAm-co-PDMDAAC are used as positive electrodes for lithium batteries.The materials were assembled into CR2025 button cell,battery capacity tester and electrochemical workstation for battery capacity and AC impedance test.Compared with free radical polymer PTAm,free radical polymer PTAm with different ion side groups.The electrical properties of PTAm-co-PSS and PTAm-co-PDMDAAC are superior.