Synthesis And Electrochemical Performance Of Polyaniline/Tin Oxide Nanorod Array

Supercapacitors are considered to be a type of novel electrochemical energy storage device because of their rapid charge/discharge,long cycle life and high power density.The design and synthesis of electrode materials is critical to the application of supercapacitors.Among the many electrode materials of supercapacitors,polyaniline(PANI)has the advantages of high theoretical capacitance,low cost and environmental protection.It is considered as a potential supercapacitor electrode material,and has good application prospect.The electrochemical performance of supercapacitors is closely related to the structure and electrical conductivity of electrode active materials.However,PANI has been not widely used due to its poor cycling stability,which is mainly due to the swelling,shrinkage and even cracking of PANI during the doping and de-doping of protons.In this paper,tin oxide nanorod array(SnO2 NRA)with good chemical stability and electrochemical stability is combined with PANI to prepare a binary composite material.SnO2 with the one-dimensional nanorods structure can effectively enhance the charge transfer efficiency.In addition,theclose contact between organic and inorganic interfaces of PANI and Sn02 NRA also effectively promote the cycling stability of PANI,and the PANI/SnO2 NRA can achieve improved electrochemical performance.In this paper,PANI/SnO2 NRA,polyaniline-reduced graphene oxide/tin dioxide nanorod array(PANI-rGO/SnO2 NRA),and polyaniline-reduced graphene oxide/nitrogen-doped tin dioxide nanorod arrays(PANI-rGO/N-Sn02 NRA)were prepared.We investigated the electrochemical properties of their single electrodes and theirpractical applications in supercapacitors.The research work of this paper includes the following aspects:(1)The synthesis and electrochemical performance study of PANI/SnO2 NRA PANI/SnO2 NRA was synthesized by the seed-assisted hydrothermal method and electropolymerization process.SnO2 NRA was grown on the surface of carbon fibers by the seed-assisted hydrothermal method,and then PANI was electrodeposited on SrnO2 NRA through electropolymerization process.As the results of scanning electron microscopy showed,the morphology of PANI/SnO2 NRA indicated that SnO2 NRA was uniformly grown on the surface of carbon fiber.After PANI was electrodeposited,the part of PANI as nanofibers with a diameter of about 100 nm was wrapped on Sn02 NRA,and another part as the layered structure was deposited on the surface of SnO2 NRA and in the interspace between SnO2 NRA.According to the charge-discharge test,the specific capacitance of PANI/SnO2 NRA electrode was 367.5 F g"1 at the current density of 0.5 A g-1.When the currrent density increased to 5 A g-1,the specific capacitance was 231.9 F g-1.The capacitance retention was 61.6%,indicating good rate performance.The results of cycling test over 2000 times at the current density of 5 A g-1 indicated that the capacitive retention of PANI/SnO2 NRA electrode was 88.3%,which exhibited good cycling stability.Based on the Polyvinyl Alcohol-sulfuric acid(PVA-H2SO4)gel electrolyte,the all-solid-state symmetric PANI/SnO2 NRA supercapacitor was assembled.In the galvanostatic charge/discharge test,the specific capacitance of the all-solid-state symmetric PANI/SnO2 NRA supercapacitor was 44.9 F g-1 at the current density of 0.2 A g-1.As the current density increased to 2 A g-1,the specific capacitance was 25.7 F g-1,and the capacitance retention was 57.2%.As the power density increased from 180 W Kg-1 to 1800 W Kg-1,the energy density decreased from 20.2 Wh Kg-1 to 11.6 Wh Kg-1.According to the cycling test,the capacitance retention of all-solid-state symmetric PANI/SnO2 NRA supercapacitor at the current density of 1 A g-1 over 2000 cycles charge/discharge was 98.0%.After the all-solid-state symmetric PANI/SrnO2 NRA supercapacitor was charged,it could light the red diodes,indicating that PANI/SnO2 NRA can be used as the electrode material for supercapacitors.(2)The synthesis and electrochemical performance study of PANI-rGO/SnO2 NRA.PANI-rGO/SnO2 NRA was synthesized by electrodepositing both PANI and rGO on SnO2 NRA through electropolymerization process.The results of scanning electron microscopy showed that PANI as nanofibers with a diameter of 100-200 nm and layered structure was wrapped on SnO2 NRA.According to the results of charge-discharge test,the specific capacitance of PANT-rGO/SnO2 NRA electrode was 624.3 F g-1 at the current density of 0.5 A g-1.The specific capacitance was 484.4 F g-1,when the current density increased to 5 A g-1.The capacitance retention was 77.6%,indicating good rate performance.2000 cycles charge/discharge test at the current density of 5 A g-1 was carried out for PANI-?GO/SnO,NRA electrode,and the capacitance retention was 96.3%,showing outstanding cycling stability.The all-solid-state symmetric PANI-rGO/SnO2 NRA supercapacitor was assembled with PVA-H2SO4 as gel electrolyte.As the current density increased from 0.2 A g-1 to 2 A g-1,the specific capacitance of all-solid-state symmetric PANI-rGO/SnO2 NRA supercapacitor decreased from 46.4 F g-1 to 39.6 F g-1,and the capacitance retention was 85.3%,exhibiting good rate performance.When the power density increased from 180 W Kg-1 to 1800 W Kg-1,the energy density decreased from 20.8 Wh Kg-1 to 17.8 Wh Kg-1.After 2000 times charge/discharge test at the current density of 1 A g-1,the capacitance retention of the all-solid-state symmetric PANT-rGO/SnO2 NRA supercapacitor was 80.8%.After the all-solid-state symmetric PANI-rGO/SnO2 NRA supercapacitor was charged,it could light red diodes.This indicated that PANI-rGO/Sn02 NRA can be used as a supercapacitor electrode material.(3)The synthesis and electrochemical performance study of PANI-rGO/N-Sn02 NRAN-SnO2 NRA was synthesized by the ammonothermal method.Then,PANT and rGO were electrodeposited on the as-prepared N-SnO2 NRA through electropolymerization process to obtain PANI-rGO/N-SnO2 NRA.The results of scanning electron microscopy showed that N-SnO2 NRA exhibited quadrangular-prism-shaped nanorod array with an edge length of 50?60 um on the surface of carbon fibers.After PANT was electrodeposited,the part of PANI in the form of nanofibers with a diameter of about 100?200 nm was wrapped in N-SnO2 NRA.Another part of PANI in the form of layers was wrapped on N-SnO2 NRA to form the core-shell structure.The diameter of wrapped N-SnO2 NRA became 100?150 nm.Depending on charge-discharge test,the specific capacitance of PANI-rGO/N-SnO2 NRA electrode at the current density of 0.5 A g-1 was 1108.4 F g-'.When the current density rose to 5 A g-1,the specific capacitance was 1028.7 F g-1.The capacitance retention was 92.8%,showing remarkable rate performance.The capacitance retention of PANI-rGO/N-SnO2 NRA electrode was 73.6%after 2000 times charge/discharge test at a current density of 5 A g-1,showing good cycling stability.The all-solid-state symmetric PANI-rGO/N-SnO2 NRA supercapacitor was assembled with PVA-H2SO4 gel electrolyte.As the current density increased from 0.2 A g-1 to 2 A g-1,the specific capacitance of all-solid-state symmetric PANI-rGO/N-SnO2 NRA supercapacitor decreased from 59.0 F g-1 to 50.9 F g-1.The capacitance retention was calculated to be 86.3%,exhibiting good rate performance.As the power.density increased from 180 W Kg-1 to 1800 W Kg-1,the energy density dropped from 26.6 Wh Kg-1 to 22.9 Wh Kg-1.After 2000 times charge/discharge test at the current density of 1 A g-1 was carried out.The capacitance retention of the all-solid-state symmetric PANI-rGO/N-SnO2 NRA supercapacitor was 56.1%.After the all-solid symmetrical PANI-rGO/N-SnO2 NRA supercapacitor was charged,it could light the red diodes.It showed that PANI-rGO/N-SnO2 NRA can be used as the potential electrode material of supercapacitor.