Sacrificial Template Fabrication And Applications Of 3D Polypyrrole Hydrogel And V₂O₃@N-C Anode Material

In recent years,micro/nano-materials with three-dimensional structure have attracted intensive interests due to their numerous applications in catalysis,drug delivery,chemical storage,optoelectronics,photonic crystals and microcavity resonance.Template method is one of the most widely used methods to establish three-dimensional complex structures.Compared with the general template method,the sacrificial template method has high application value due to its advantages of more simple and efficient in building 3D structure.In this paper,vanadium pentovanadate(NH4NO3)was used as vanadium source to synthesize vanadium pentovanadate aqueous sol through hydrothermal synthesis method.Then,3D polypyrrole hydrogel(PHG)beads and V2O3@N-C nanosheets were synthesized through sacrificial template method.The morphology,structure and composition of PHG beads and V2O3@N-C nanosheets were characterized,and their applications in organic dye adsorption and lithium ion batteries were explored.Firstly,in this paper,the PHG beads were prepared by in situ polymerization through sacrificial template method.The PHG beads were purified by repeated washing and then its application in organic dye adsorption were explored.The results shows that the PHG beads have excellent adsorption performance.Its adsorption capacity for MO dyes reaches 236.9mg·g-1,and the effective adsorption concentration is as low as 0.4 ppm.Moreover,the PHG beads have good reproducibility,and the adsorption retention rate reaches 80%after repeated experiments for three times.In the experiment,the influence of different factors on the adsorption performance of PHG beads is explored,such as temperature,PH value,etc.Its adsorption isotherms and adsorption kinetics is explored.In addition,the PHG beads can be considered as a potential selective adsorbent for the mixture of MO dye(anionic dye)and MB dye(cationic dye).Secondly,the V2O5 was used as the precursor to synthesize V2O5@PPY dispersion in water.Then the V2O3@N-C nanosheets were prepared by freeze-drying and annealing,subsequently.Compared with pure V2O3 electrode materials,the electrochemical properties of the prepared V2O3@N-C nanosheets have been tremendously improved.After 100 cycles at current density of 0.2 A·g-1,the reversible specific capacity of V2O3@N-C nanosheets retains 651.5 mAh·g-1.After 1000 cycles under the high current density of 1 A·g-1,the reversible specific capacity of V2O3@N-C nanosheets retains 306.8 mAh·g-1.the reversible specific capacity retention rate reaches 80.6%and the average capacity attenuation rate is 0.02%.In conclusion,V2O3@N-C nanosheets can be considered as a high-performance lithum ion anode material with good application prospects due to its high reversible specific capacity,good rate performance,excellent long-term cycle stability.