一步水热法制备钠离子电池正极材料Na3V2（PO4）2F3及其性能研究

One Step Hydrothermal Synthesis and Electrochemical Performances of Na3V2（PO4）2F3 as Cathode Material for Sodium-ion Batteries

采用一步水热法制备了钠离子电池正极材料Na3V2(PO4)2F3,用XRD、SEM、恒流充放电等对样品进行了表征。研究表明,络合剂种类对Na3V2(PO4)2F3的结构、形貌及电化学性能有重大影响,以抗坏血酸、柠檬酸、草酸和酒石酸为络合剂制备的样品分别为小立方体、球形、大立方体和不规则球状,除以酒石酸为络合剂制备的样品为无定形结构外,其余样品均结晶良好。其中以抗坏血酸为络合剂制备的样品结晶度最高且电化学性能最优,该样品在0.05 C和0.5 C倍率下的首次放电比容量为112.0 mAh/g和92.5 mAh/g,且具有良好的倍率性能和循环性能。

The cathode material Na3V2(PO4)2F3 for Na-ion batteries were prepared by a one-step hydrothermal method,and the samples were characterized by XRD,SEM and galvanostatic discharge-charge methods.The results show that sorts of complexing agents have great influences on the structure,morphology and the electrochemical properties of Na3V2(PO4)2F3.Using ascorbic acid,citric acid,oxalic acid and tartaric acid as complexing agent,the surface morphologies of samples are small cube,spherical,large cube and irregular sphere,respectively,and except the sample prepared with tartaric acid presents amorphous structure,other three samples all have good crystallization.Among them,the sample made with ascorbic acid shows the highest crystallinity and the best electrochemical properties.The sample shows the initial specific discharge capacities of 112.0 mAh/g and 92.5 mAh/g at the rates of 0.05 C and 0.5 C,and has good rate capability and cycling ability.