Preparation And Electrochemical Performance Of Polytriphenylamine Derivatives As Organic Electrode Material

In this paper,a series of triphenylamine polymer derivative materials were synthesized:（1）Triphenylamine derived polymer which containing quinone structure（PBDPAA）;（2）Poly（phenylaniline）functional polymer material（P（Ph An））;（3）A series of crosslinked porous organic polymers（POPs）.On this basis,they are used as the organic cathode electrode material to study its electrochemical and lithium-ion battery performance,the concrete work is as follows:2,6-bis（Diphenylamino）-9,10-anthraquinone（BDPAA）functional monomer was synthesized by Buchwald Hartwig aromatic amination reaction with 2,6-dibromo anthraquinoneanddiphenylamineasmonomers,afterthat,Poly（2,6-bis（Diphenylamino）-9,10-anthraquinone）（PBDPAA）functional materials were obtained by chemical oxidation polymerization.Under SEM,it was observed that the material showed loose and sea urchin like spatial stacking structure.The successful introduction of carbonyl was confirmed by FT-IR and ¹H NMR,indicating that the synthesis was successful.Cyclic voltammetry showed that there were two pairs of redox peaks at 3.849/1.847 V and 4.341/3.721 V,which belonged to the redox process of quinone structure and aniline unit respectively.As the cathode material of lithium battery,at the current density of 20 m A·g^-1,the specific capacity of PBDPAA material is 184.6m Ah·g^-1at the first turn.after 50 cycles,the specific capacity of PBDPAA material is about 93 m Ah·g^-1,at the current densities of 20,50,100,200 and 500 m A·g^-1the stable discharge specific capacities are 119.3,104.9,92.1,90.3 and 79.7 m Ah·g^-1,respectively.Compared with PTPA material,the cycle performance and rate performance are significantly improved.Polyphenylaniline（P（Ph An））functional materials were prepared by polycondensation with 4-bromodiphenylamine as monomer through Buchwald Hartwig C-N coupling reaction.The spatial configuration similar to honeycomb stacking state was observed under SEM.The characteristic absorption peaks of benzene ring and tertiary amine group were determined by FT-IR,indicating that the synthesis was successful.The cyclic voltammetry curve of P（Ph An）material shows a pair of broad redox peaks at3.719/3.383 V,which corresponds to the increase of the density of active N atoms.As the cathode material of lithium battery,at the current density of 20 m A·g^-1,the specific capacity of P（Ph An）material is 133 m Ah·g^-1,after 50 cycles,84%of the initial capacity was maintained.The stable discharge specific capacities of P（Phan）at 20,50,100,200and 500 m A·g^-1rates are 119.9,118.3,115.4,111.7 and 104.7 m Ah·g^-1respectively.Compared with PTPA materials,the cycle performance and rate performance are significantly improved.PTPA materials with different crosslinking degrees（POP-I,POP-II,POP-III）were prepared by Friedel Crafts reaction with anhydrous ferric chloride（Fe Cl₃）as initiator,triphenylamine as monomer and FDA as crosslinking agent.The characteristic peaks corresponding to methylene structures at 2854 cm^-1and 2921 cm^-1were captured in the FT-IR spectrum.SEM photos showed that POPs with different crosslinking density showed differential porous spatial structure,benefiting from this,POPs materials generally show lower impedance and better ion diffusion ability in impedance test.The electrochemical CV curve showed that there were two pairs of redox peaks at 4.051/3.603V and 3.488/2.525 V,corresponding to the redox process characteristics of triphenylamine active center in POPs materials and the carbonyl redox platform in cross-linked structure.As the cathode material of lithium battery,in the first cycle of current density of 20 m A·g^-1,the specific capacities of POPs materials are 102.1（POP-Ⅰ）,96.4（POP-Ⅱ）and 61.4（POP-Ⅲ）m Ah·g^-1respectively.POP-â…¡still has 97.6%of the initial capacity at high magnification,it shows that polymer POPs materials with appropriate doping degree can be used as potential high power density electrode materials for lithium battery cathode.