Preparation Of Polyaniline-Based Composites And Its Application In Zinc Batteries

Zinc secondary batteries are a kind of potential energy conversion devices because of their high theoretical specific capacity and abundant reserves.The development of suitable positive electrode materials is the most important research.Conductive polymer polyaniline(PANI)has good redox reversibility and high theoretical specific capacity,and has low production cost and no environmental pollution.It is an excellent electrode candidate material,but PANI synthesized by economical chemical oxidation method is very easy to agglomerate to hinder the dedoping of ions,resulting in low specific capacity and poor cycle performance.It is an important means to improve the physical properties and chemical properties by introducing other materials.Graphene has excellent properties such as high electron mobility and high specific surface area at room temperature,and graphene oxide(GO)has good water solubility due to the presence of its oxygen-containing groups,and is prepared for constructing a hybrid nanocomposite based on GO.The conditions,and PANI are easily combined with the ?-? interaction of GO,so graphene oxide is a good doping material for PANI.In this paper,PANI was polymerized using GO as a template,and PANI/GO composites were modified by transition ions.The morphology and structure of PANI compositions were characterized by FE-SEM,XRD,FT-IR and BET tests.As a positive electrode,polyaniline composites were assembled into zinc secondary batteries,and their electrochemical properties were tested by EIS,CV and GCD tests.The modified Hummers method was used to synthesize GO,and the PANI/GO composite was synthesized by using GO as a template.The agglomeration of PANI and GO were obviously weakened.PANI was wrapped on the surface of GO material.There was no significant change in the XRD and FT-IR curves,but the ?-? interaction between PANI and GO caused a slight shift in the characteristic absorption peak of polyaniline.The charge transfer resistance of the assembled zinc-polyaniline secondary battery was greatly reduced,the area and current of the CV curve were increased,and the batterys were subjected to constant current charge and discharge test and rate charge and discharge After doping GO,the cycle performance,capacity and rate performance of PANI have been greatly improved.The PANI/GO-NaBH4 and PANI/GO/Co3O4 composites were synthesized and found to reduce the oxidation degree of GO by using NaBH4 to reduce the oxidation degree of GO.The electrochemical performance of PANI graphene composites was not improved,and PANI/GO/Co3O4 ternary composite The electrochemical properties of the materials also improved significantly,and PANI,GO,and Co3O4 acted synergistically.The transition ions(Zn2+,Fe3+,Co2+)were added during the in-situ polymerization to further modify the PANI/GO to increase the charge delocalization in the PANI backbone and thus increase the conductivity.Pseudoprotonation occurred between the empty d-orbitals from the transition metal ions and the imine N atoms in the polyaniline structure.The transition ions complexed with the nitrogen atom on the imino group on the anthracene ring of the PANI macromolecular chain and formed interchain chains between several adjacent polyaniline chains by coordination.Therefore,after transition ions doping,PANI/GO has a more pronounced short rod structure and cross-linked with each other.The conductivity of composites was improved and the charge transfer resistance was reduced.The area of the CV curve was also increased to a different extent,so that the capacity and cycle stability of the material were improved.The hydrophobic hydrophilic material polyaniline and the hydrophobic material PTFE were mixed together to form a hydrophobic permeable electrode of polyaniline to be in contact with oxygen in the air.Assembled it into a battery with a zinc sheet,and subjected to electrochemistry tests such as EIS and constant current discharge test.Compared to zinc-polyaniline batteries,the discharge capacity of the battery(from 60 mAh to 925 mAh)is greatly increased and has a relatively stable discharge voltage(0.85 V).The excess discharge capacity of the battery comes from the oxidation of the reduced polyaniline by oxygen.Large-capacity discharge is achieved by catalytic oxygen reduction.Finally,the application of polyaniline-based materials in the market of zinc secondary batteries and the cost budget of the polyaniline graphene materials were studied,PANI/GO has become the advantage of its high electrochemical performance,low production cost and easy synthesis.Zinc secondary batteries have potential cathode materials.