Construction Of Polyaniline Hydrogel Composite Systems And The Application In Zinc Ion Batteries

Aqueous zinc-ion batteries have attracted increasing attention due to their high safety,low cost,and good electrochemical performance.However,due to the high polarization characteristics of Zn²⁺and the narrow potential window in which aqueous electrolytes can exist stably,it is crucial to develop suitable cathode materials for Zn-ion batteries.Owing to the typical nanoporous structure,3D interconnected conductive framework and inherent pseudocapacitive properties of polyaniline hydrogels,which can endow electrode materials with good electronic/ionic conductivity,structural stability and electrochemical activity,this thesis developed a research on the cathode material of zinc ion battery based on polyaniline hydrogel composite system.Based on this,three different polyaniline hydrogel composite systems（ie:polyaniline composite hydrogel with 3D nanofiber structure,polyaniline-polyimide composite hydrogel and polyaniline-manganese dioxide composite hydrogel system）,and its electrochemical zinc storage properties were studied.The main findings and conclusions of this paper are as follows:1.In this paper,a new conductive polymer hydrogel（PANI-SDBS）was first synthesized based on the self-assembly of polyaniline and anionic surfactant sodium dodecylbenzenesulfonate（SDBS）.Because of the intermolecular electrostatic interaction andπ-πconjugation,PANI-SDBS has a well-arranged fibrous micromorphology and enhanced mechanical strength.Using PANI-SDBS as a cathode material for Zn-ion batteries,the results indicate that the 3D continuous fiber structure of PANI-SDBS is beneficial to the doping/de-doping kinetics,rate performance,and excellent cycling stability of the electrode(81.7%of capacity retention after 1500 discharge/charge cycles at 0.5A g^-1).This study confirms that the polyaniline composite hydrogel is a promising cathode material for zinc-ion batteries.2.Polyimide electrode material（PUI）was synthesized using perylene-3,4,9,10-tetracarboxylic dianhydride（PTCDA）and Urea,which was combined with nanoporous polyaniline hydrogel,The polyaniline-polyimide hydrogel composite system（PANI-PUI）zinc-ion battery cathode material was obtained.Studies have shown that the electrochemical performance of PANI-PUI has been greatly improved compared with PUI.For example,the specific capacity has been increased by 72%,and the rate performance and cycle stability have also been significantly improved.Electrochemical kinetic analysis revealed that nanoporous polyaniline can facilitate fast electron/ion transport and high capacitance contribution during discharge and charge.Furthermore,mechanistic analysis revealed that in PANI-PUI,the C=O of PUI and the C=N-functional group of PANI have synergistically enhanced electrochemical zinc storage capacity.This work shows that nanoporous structures with good electronic/ionic conductivity can be effectively promoted by compounding with polyaniline hydrogels,which can effectively promote the release of ideal electrochemical properties from polyimide electrode materials,and provide a basis for the research and development of high-performance organic Cathode materials for zinc-ion batteries provide a reference.3.In order to stimulate higher electrochemical zinc storage capacity in the polyaniline hydrogel composite system,this chapter carried out the research on the in situ synthesis of manganese dioxide in the polyaniline hydrogel composite system:using PANI-SDBS（see Part I）.When polyaniline and SDBS are self-assembled to synthesize polyaniline,different concentrations of Mn SO₄ are added to generate Mn O₂ in situ through oxidation and subsequent hydrothermal treatment.Microstructural observations revealed that the composite hydrogels exhibited in situ generated manganese dioxide particles on nanofibrous ribbons in addition to the 3D fibrous structure.The electrochemical test results show that the specific capacity of the PANI-Mn O₂ composite hydrogel is up to 84%higher than that of the PANI-SDBS hydrogel(when the cell density is 0.1A g^-1,the specific capacity is It is improved from 131m Ah g^-1 to 241m Ah g^-1),which confirms the effectiveness of the method proposed in this paper.This study provides a reference for the construction of polyaniline hydrogel composite systems with high electrochemical zinc storage capacity.Due to time constraints,the structural regulation of the system and related mechanism studies have not yet been completed.