Preparation And Electrochemical Performance Of Thioquinone Polymer Cathode Material For Water Zinc Ion Batteries

Since the 21st century,aqueous zinc-ion batteries have attracted the attention of many scholars due to their low cost and environmental friendliness.Among them,the organic electrode material shows the characteristics of high theoretical capacity,flexible structure and stable electrochemical performance,and is expected to be called the cathode material of a new generation of aqueous ion batteries.However,compared with inorganic materials,organic materials still have many shortcomings in conductivity,capacity and solubility.Therefore,the current research focus is on designing an organic material to improve the above problems.Thiopolymer macromolecules contain C-S bonds,which are an organic material with research prospects.In this project,the following aspects are studied around thioquinone polymer macromolecular materials:（1）The thioquinone polymer material PTQS was synthesized by hydrothermal synthesis method（80℃、100℃、120℃）using tetrachlorobenzoquinone and sodium sulfide as raw materials.Among them,the PTQS-1 material synthesized at 100℃has the best electrochemical performance.After X-ray photoelectron spectroscopy（XPS）and Fourier transform infrared spectrometer（FT-IR）testing,it was found that the polymer material structure contains C-S bonds and there is an oxidation-reduction active group C=O.The cyclic voltammetry test results show that the material has good redox reversibility.In the rate test of 0.02 A g^-1,the highest discharge capacity of PTQS-1 material is 151.1 m Ah g^-1;In the 200 cycle test of 0.1 A g^-1,the first cycle discharge capacity of PTQS-1 was 161.2m Ah g^-1,and the capacity retention rate was 53%.（2）Using reduced graphite oxide（rGO）and PTQS as raw materials,PTQS/rGO（2:1、5:1、8:1）was prepared by in-situ composite method.The test showed that PTQS/rGO-1（5:1）had the best performance.The highest discharge capacity of PTQS/rGO-1 material was 227.3 m Ah g^-1in a rate test of 0.02 A g^-1;In the 200 cycle test of 0.1 A g^-1,the first cycle discharge capacity of PTQS/rGO-1 was 207.4 m Ah g^-1,and the capacity retention rate was 81%.This indicates that the layered structure and excellent conductivity of rGO can significantly improve the rate performance and cycle retention of PTQS.（3）A novel organic quinone thiopolymer material PNQS was synthesized using2,3-dichloro-1,4-naphthoquinone and sodium sulfide（2:1、1:1、1:2）as raw materials.The electrochemical performance of PNQS-1（1:1）polymer material was found to be the best.In the rate test of 0.02 A g^-1for PTQS-1 material,PNQS-1 polymer material reached the highest discharge capacity of 195.1 m Ah g^-1;In the 100 cycle test,when the discharge capacity of PNQS-1 in the first cycle is 181.6 m Ah g^-1,the capacity retention rate is 60%.