Research On Electrochemical Performance Of Lanthanum Based Perovskite Electrode Materials For Supercapacitors

The research of perovskite metal oxides is a hot topic in the field of energy storage.It has the advantages of low impedance and large capacity when applied in supercapacitors.In this paper,LNO and LMO perovskite metal oxide electrode materials were prepared by electrospinning method and applied in supercapacitors.The electrochemical performance of electrode materials was improved by modification.Thus,the application of lanthanum based perovskite metal oxides in supercapacitor system was studied.In this paper,LaNiO₃ precursor was prepared by electrospinning and then annealed at high temperature to achive porous structrue.By adjusting the spinning voltage,the size of LaNiO₃ particles were regulated.Thus by adjusting the annealing temperature the degree of crystallization of the material were regulated.Finally,by adjusting the molar ratio of La and Ni,the amount of active substance were regulated.Then the spinning voltage,element molar ratio and annealing temperature were optimized by electrochemical test.Next,precursor of LaNiO₃ was prepared by sol-gel method,and the specific surface area of LaNiO₃ particles was regulated by adjusting the content of template material（PAN）.Subsequently,LaMnO₃ precursor was prepared by electrospinning and annealed at high temperature.The spinning voltage,element ratio and annealing temperature were optimized by similar electrochemical test.Finally,LaNiO₃ and LaMnO₃ materials were modified with sodium borohydride to introduce crystal defects,and the electrochemical performance changes before and after modification were explored.LaNiO₃ materials prepared by electrospinning method has good electrochemical performance.The electrochemical performance of the sample prepared at 9 k V spinning voltage,1:2 lanthanum nickel ratio and 700℃annealing temperature is the best.The capacity of single electrode system can reach 75.45 F/g at 0.5 A/g current density.Under double electrode system,the power density and energy density can reach 1440 W/kg and8 Wh/kg at 2 A/g current density,while at the current density of 30 A/g,the power density and energy density can reach 23400 W/kg and 0.0013 Wh/kg.After modification by NaBH₄,the capacity of the device reaches 90 F/g at 0.5 A/g current density.Under double electrode system,the power density and energy density can reach 1550 W/kg and 12.06Wh/kg at 2 A/g current density,while at the current density of 30 A/g,the power density and energy density can reach 23250 W/kg and 0.043 Wh/kg,which indicates the electrochemical performance has been improved.LaMnO₃ materials prepared by electrospinning method has good electrochemical performance.The electrochemical performance of the sample prepared at 9 k V spinning voltage,1:2 lanthanum nickel ratio and 700℃annealing temperature is the best.The capacity of single electrode system can reach 46.26 F/g at 0.5 A/g current density.Under double electrode system,the power density and energy density can reach 1550 W/kg and4.4 Wh/kg at 2 A/g current density,while at the current density of 30 A/g,the power density and energy density can reach 23250 W/kg and 0.003 Wh/kg.After modification by NaBH₄,the capacity of the device reaches 58.18 F/g at 0.5 A/g current density.Under double electrode system,the power density and energy density can reach 1550 W/kg and18.07 Wh/kg at 2 A/g current density,while at the current density of 30 A/g,the power density and energy density can reach 23250 W/kg and 0.136 Wh/kg,which indicates the electrochemical performance has been greatly improved.These work indicates that while lanthanum based perovskite metal oxides has low capacitance when applied in supercapacitance,it has very high power density which could help researching on micro-supercapacitors.