Preparation And Research Of Cathode Materials For Piperazine Tetraketones Of Lithium Ion Batteries

Prompted by the remarkable development of energy storage devices,intense research interest has been focused on the exploration of lithium-ion batteries containing high energy density.The properties of batteries depend largely on the characteristics of the cathode materials.At present,although inorganic cathode materials are used for large-scale applications,there are many shortcomings and deficiencies.Compared with inorganic cathode materials,the high electrochemical performance,safety,environmental friendly,in addition with the unique features of organics such as structure diversity and structure-designed,provide them great perspective in various energy storage devices.However,the development and application of organic carbonyl compounds in electrode materials are mainly severely limited in two ways:(1)Organic carbonyl compounds are easily dissolved in the electrolyte,resulting in a sharp decline in battery charge and discharge capacity,which seriously affects their electrochemical performance;(2)The organic compound is insulating and the material has low conductivity,which is not conducive to the diffusion of lithium ions in the material,resulting in poor battery rate performance.In view of the above problems,this paper intends to design and synthesize organic cathode materials with high capacity and good conductivity.Through simple chemical synthesis and molecular structure design to improve the solubility and electronic conductivity of the materials,increase the Coulomb efficiency,and prepare organic cathodes material with excellent performance.This research mainly explores from the following parts:(1)Using oxalyl chloride and oxalamide as raw materials,through simple chemical synthesis,an active substance of 2,3,5,6-piperazine tetraone was prepared,and the structure of the active substance was verified by infrared spectroscopy,mass spectrometry,and nuclear magnetic resonance.,Test its electrochemical performance by electrochemical measurement technology.The test results show that although the active material has a higher initial discharge capacity,its solubility in the electrolyte is more problematic.(2)Aiming at the problem of easy dissolution of carbonyl compounds,starting from molecular structure design,1,4-bis(9,10-dioxo-9,10-dihydroanthracene-2-yl)Piperazine-2,3,5,6-tetraone(BDHPT).The structure of the active material was verified by infrared spectroscopy,mass spectrometry,and nuclear magnetic resonance,and the compound was further used as a cathode material for lithium ion batteries for electrochemical performance tests,and their electrochemical performance was compared.Due to the introduction of rigid groups in the molecular structure,which increases the ? conjugation in the molecular structure,so that the structural stability of the material is enhanced.After 50 cycles at 0.1 C,the capacity retention rate was69.5%.(3)Preparation of 1,4-bis(9,10-dioxo-9,10-dihydroanthracen-2-yl)piperazine-2,3,5,6-tetraone/CNT(BDHPT/CNT)composite.Through the electrochemical performance test of the material,it is concluded that under different magnifications,the performance of BDHPT/CNT is significantly better than that of BDHPT.Structural analysis may be due to BDHPT entering the pore diameter of CNT,on the one hand,increasing the contact between BDHPT and CNT,thereby increasing the conductivity of the active material;on the other hand,inhibiting the dissolution of BDHPT in the electrolyte,thus improving the cycling performance of the battery.