Preparation Of Quinone Materials And Its Performance In Aqueous Electrochemical Energy Storage

Aqueous batteris have great application prospect in the direction of energy storage because of their high security and high ionic conductivity.Quinone materials as electrode materials for aqueous batteries have the advantages of high theoretical capacity,controllable structure and low cost.However,their development is limited by such problems as capacity attenuation,low charge transfer rate and unclear energy storage mechanism.Based on this,in order to solve the above problems,this thesis improves its electrochemical performance by constructing conductive network,forming crosslinked structures by polymerization and constructing new conjugate structures.The details are as follows:（1）A three-dimensional porous network structure was constructed by hydrothermal method,and TCNQ was successfully combined with reduced graphene oxide（r GO）.FTIR,XRD,Raman,SEM and XPS tests were used to demonstrate the successful recombination of TCNQ.As the positive electrode material of aqueous ammonium-ion battery,TCNQ-r GO has better performance than pure TCNQ in aqueous ammonium-ion battery.At the current density of 1 A g^-1,the current capacity can reach 92.7 m Ah g^-1,and at the high current density of 10A g^-1,the long cycle stability is more than 5000 cycles.In-situ Raman and ex-situ XRS techniques are used to analyze and characterize the electrochemical reaction kinetics of TCNQ-r GO in aqueous ammonium-ion batteries,further confirming the reversible electrochemical behavior of the active site of TCNQ-r GO and NH₄⁺（de）insertion.（2）Swelling of the cross-linked structure of PQANS prepared by conjugate addition reaction during charging and discharging is conducive to the entry of ions in the electrolyte,but it is not easy to dissolve.This structure ensures its stability and improves its electrochemical performance.PQANS has excellent cyclic stability,with a discharge capacity of 126.2 m Ah g^-1 after 300 cycles and a capacity retention rate of 98.44%.The structure of PQANS electrode and its energy storage mechanism during H⁺（de）inserting are studied by a series of in-situ Raman and ex-situ XPS test methods.Assembled PQANS//Mn O₂ battery,specific capacity can reach 54.8 m Ah g^-1,capacity retention rate of 97.99%.It provides a new idea for the practical application and future development of organic quinone electrode materials in APBs.（3）A new conjugate structure of PTO-AQ was prepared by dehydration condensation.The results of XRD,FTIR,SEM,XPS and Raman tests demonstrate the successful synthesis of the PTO-AQ structure.Due to its excellent conductivity brought by conjugated structure and abundant active sites on its structure,PTO-AQ has high specific capacity.Under the current density of 1 A g^-1,the discharge capacity can reach 117.9 m Ah g^-1,and the capacity retention rate is 74.3%after 500 charge-discharge cycles.Through a series of in-situ Raman and ex-situ XPS tests,the redox behavior of PTO-AQ and Na⁺（de）insertion process during charging and discharging are studied.