High performance asymmetric supercapacitor device based on lanthanum doped nickel-tin oxide/reduced graphene oxide composite

Doping is the most promising approach to improve the electrochemical performance of metal oxide-based supercapacitor. Rare-earth element doping is helpful to improve the electrochemical performance of metal oxides due to the presence of unique 4f electronic configuration. Herein, Lanthanum (La) doped Nickel-tin oxide/reduced graphene oxide (LNSRG) composite was successfully prepared via one-step hydrothermal method. The optimized LNSRG 2 composite exhibited similar to 1238 F g(-1) specific capacitance at 3 A g(-1) current density using 6 M KOH as electrolyte. The effect of electrolyte's pH on the electrochemical performances was investigated using various electrolytes. The asymmetric supercapacitor (ASC) device fabricated with LNSRG 2 as positive electrode material and sonochemically reduced graphene oxide (SRGO) as negative electrode material exhibited energy density of similar to 38 W h kg(-1) at a power density of similar to 870 W kg(-1) in the potential window of similar to 1.6 V using 1 M Na2SO4 as electrolyte. The ASC device retained similar to 75 % of its initial capacitance after 10,000 continuous charge-discharge cycles at 15 A g(-1) current density. Two ASC devices connected in series was capable of powering a 1.8 V red LED light.

Automated summary

Doping with rare-earth elements, a one-step hydrothermal method was used to prepare La-doped Ni-Sn oxide/reduced graphene oxide composite. The electrochemical performance of the composite was studied under different electrolyte conditions, and the LNSRG 2 composite showed good specific capacitance in 6M KOH electrolyte. An ASC device fabricated with LNSRG 2 and SRGO as positive and negative electrode materials, respectively, exhibited high energy density and good cyclic stability in 1M Na2SO4 electrolyte.