Preparation And Sodium/potassium Storage Performance Of Electrode Materials Based On Perylene Tetracarboxylic Dianhydride

Lithium ion batteries（LIBs）have been widely applied in energy storage equipments due to its high energy density.However,the global shortage and uneven distribution of lithium resource make the increasing production cost of LIBs a concern.Therefore,developing energy storage device with abundant reserves and low price has become a primary duty for researchers.Among the numerous metal elements,sodium,potassium and lithium are located in the same major group,exhibiting similar electrochemical properties.Besides,sodium and potassium are much more abundant than lithium,which makes sodium ion batteries（SIBs）and potassium ion batteries（PIBs）expected to be ideal substitutes for LIBs.During the investigations of SIBs and PIBs,it was found that the lack of high-performance cathode and anode is the main restraint on its development.Herein,in this study,3,4,9,10-perylene tetracarboxylic dianhydride（PTCDA）organic macromolecular was used as the raw materials for the carbon anode and organic cathode by carbonization-doping and compounding with graphene oxide（GO）,respectively,assembling full batteries and investigating the potassium storage performance.The main researches of this paper are as follows:（1）3D sulfur/oxygen codoped soft carbon materials for the storage of sodium and potassium.Sulfur/oxygen codoped soft carbon（SO-SC）was prepared using PTCDA as carbon precursor and sublimated sulfur as sulfur source by a simple ball milling-heat treatment technique.The ball-milling process facilitates the morphology change from irregular shapes to regular agglomerates,which is helpful for decreasing the contact area of electrode/electrolyte,and thus enhancing the initial coulombic efficiency（ICE）.In addition,the introduction of sulfur and oxygen doping sites in carbon materials increases the interlayer distance and the storage sites for Na⁺and K⁺.Based on these desirable characteristics,the SO-SC electrode for SIBs anode exhibits a high ICE（61.3%）,excellent rate capability(230.7 m Ah g^-1 at 2 A g^-1)and superior cyclic stability(a high capacity retention of 86.9%after 4000 cycles at 2 A g^-1).Furthermore,when used as PIBs anode,the SO-SC electrode displays a high discharge capacity(412.6 m Ah g^-1),remarkable rate performance and cyclic stability.（2）PTCDA/reduced graphene oxide as a self-supporting electrode for potassium storage.In this work,an ultrasonic method was adopted to promote the homogeneous mixture of PTCDA and GO,and then the PTCDA/reduced graphene oxide（PTCDA/RGO）self-supporting electrodes were obtained by freeze-drying and thermal reduction process.It was found that the optimized PTCDA/RGO-1 sample exhibits the best rate performance(70.7 m Ah g^-1 at 0.5 A g^-1)and cyclic stability(63.3 m Ah g^-1 at0.2 A g^-1 after 1200 cycles).Finally,the PTCDA/RGO-1 was selected as cathode,SO-SC,graphitized PTCDA（G-PTCDA）and potassium 3,4,9,10-perylenetetracarboxylate/expanded graphite（K₄PTC/EG）as anode to assemble PIFCs,respectively.It was demonstrated that PTCDA/RGO-1//G-PTCDA PIFCs present the highest discharge plateau（2.45 V,1.6 V）,and PTCDA/RGO-1//SO-SC full cells display the best rate properties(69.1 m Ah g^-1 at 0.5 A g^-1)and cyclic stability(63.3 m Ah g^-1at 0.2 A g^-1 after 1200 cycles,a high capacity retention of 83.5%).Interestingly,practical application testing results show that all three types of full batteries can make the thermometer and the LED light with the word HNU work properly.