Perylene Diimide Based High Performance Organic Electrodes For Secondary Ion Batteries

In recent years,with the explosive growth of electric vehicles and consumer electronics,the demand for lithium ion batteries?LIBs?is increasing.As the important raw material for LIB electrodes,the consumption of lithium and other relating mineral materials such as cobalt is increasing.However,limited mineral resources restrict the sustainable development of LIBs.The environmental pollution and high energy consumption caused by the mining,processing and recycling of these mineral resources cannot be ignored.In contrast,organic electrode materials with light weight,abundant raw materials and environmental friendliness have received increasing attentions.However,due to the lack of suitable processing methods and the proper battery design,organic LIB electrode materials have not achieved the desired development.On the other hand,the development of secondary ion batteries based on other high-abundance elements such as sodium and magnesium is also a good alternative to LIBs.In this respect,organic electrode materials could be used to store metal ions other than lithium ions.In this thesis,the classical organic electrode material,3,4,9,10-perylenetetracarboxylic diimide?perylene diimide,PDI?was selected as the model compound.A high performance organic LIB electrode based on PDI was prepared by solution processing,which was applied to the actual device flexible LIB.In addition,a magnesium ion organic secondary battery based on PDI derivatives has also been developed.The specific research contents are as follows:?1?Solution-processed perylene diimide/carbon clothes?PDI/CC?as integrated cathodes for flexible lithium ion batteries:Firstly,PDI was dissolved by acid solution with different solid content and then soaked with CC to obtain PDI/CC integrated electrodes with different load of PDI.And next,Ultraviolet spectrum?UV?,Fluorescence spectrum?FL?,X-ray diffraction analysis?XRD?,Raman spectrum,Scanning electron microscope?SEM?and X-ray photoelectron spectroscopy?XPS?were employed respectively and the corresponding characterization results have distinguished our acid-pasting method from that based on traditional 1-Methyl-2-pyrrolidinone?NMP?.Subsequently,these electrods were applied as the cathodes for LIBs and their electrochemical performance were measured.The results showed that the PDI/CC integrated electrodes prepared under the solid content of 20 mg mL^-1 exhibited the best electrochemical performance.At the current density of 50 mA g^-1,it displayed high specific capacity of 136 mAh g^-1.At the current density of500 mAh g^-1,it showed 126 mAh g^-1 of the specific capacity and the capacity retention could achieve 83%even after 300 charge/discharge cycles.Finally,the optimized PDI/CC integrated cathode was coupled with a pre-lithiated carbon cloth anode to fabricate a flexible lithium ion battery.This flexible lithium ion battery could still maintain good galvanostatic charge-discharge performance and cycling stability under different bending state,suggesting the potential application value of PDI/CC integrated cathode in flexible lithium ion battery.?2?Perylene diimide derivate based magnesium ion organic secondary batteries:Firstly,perylene diimide–ethylene diamine?PDI-EDA?and polytriphenylamine?PTPAn?were synthesized by the polycondensation and oxypolymerization methods,respectively.And next,the cyclic voltammetry?CV?curve of these two materials were measured in a three electrode system containing 1 M Mg?ClO₄?₂/acetonitrile?AN?solution and the results showed that the redox potentials of PDI-EDA were about 2.14and 1.90 V vs.Mg/Mg²⁺,while that of the PTPAn were located at about3.13 and 3.26 V vs.Mg/Mg²⁺.Subsequently,a magnesium ion organic secondary battery was assembled utilizing PDI-EDA as anode,PTPAn as cathode and 1 M Mg?ClO₄?₂/?AN?solution as electrolyte and its electrochemical performance was aslo investigated.And the obtained magnesium ion organic secondary battery exhibited good rate performance with a specific capacity of 90 mAh g^-1 and 73 mAh g^-1 at the current density of 50 mA g^-1 and 1000 mA g^-1,respectively.It also showed superior cycling stability,reserving 88%of the initial specific capacity even after 5000charge/discharge cycles at the current density of 1000 mA g^-1.Besides,the good electrochemical performance of our magnesium ion organic secondary battery can still be reserved even at the low temperature of-10^oC or under severe bending state in the flexible pouch cell.The excellent performance of the battery can be attributed to the synergistic effect of the dual-ion energy storage mechanism and the utilization of organic electrode materials.