The Research On The Novel Cathode Materials For Aqueous Zinc Battery

Nowadays lithium ion batteries have dominated the market of consumer electronics products and gradually developed in the fields of electric vehicles and large-scale energy storage.However,its development is still limited by the lithium reserves,high prices and the flammable safety problems caused by organic electrolytes.Recently,the secondary aqueous zinc-ion batteries have gradually attracted the attention of researcher with high safety and low prices,which is regarded as the optimal choice for large-scale energy storage.However the aqueous zinc batteries is bottlenecked by the cathode materials.The main contents and results are listed as follows:?1?V₂O₅ nanopaper is applied as the new Zn-ion battery cathode material.Such material consists of V₂O₅ nanofibers and carbon nanotubes?CNTs?.V₂O₅ is chosen as the redox active cathode framework because it has multiple oxidation states and layered crystalline structure,which can reversibly insert/extract Zn ions.The nanofiber morphology endows the material with short ionic diffusion distance and is stable after repeating Zn-ion insertion/extraction.The CNTs entangled between the V₂O₅ nanofibers serve as the excellent electron conducting network.Due to the above advantages,the material delivers a capacity of 375 mA h g^-1 and 80%capacity retention over 500 cycles.Besides,the synthesis method is easy to scale up and the obtained V₂O₅ nanopaper can be handled just like regular paper.These properties are benificial for large scale energy storage.?2?The surface modified 7,7,8,8-Tetracyanoquinodimethane?TCNQ?with poly?3,4-ethylenedioxythiophene??PEDOT?was firstly applied as the cathode material for aqueous zinc batteries.Herein we got TCNQ@PEDOT by surface coating of TCNQ.The presence of the coating layer was verified using IR,TEM.The length of PEDOT coating layer is around 4.3 nm.The reaction mechanism was studied by CV and Galvastatic charge and discharge.It was proved that PEDOT coating layer has improve the cycle and rate performance.TCNQ@PEDOT shows a discharge capacity of 201 mAh g^-1 at 0.1 A g^-1,and has a capacity retain of 100 mAh g^-1 for 100 cycles at 1.0A g^-1.XRD and SEM were used to see the difference of cathode under charging and discharging,and it was found that TCNQ had a large morphology change after discharge.