Sr-doped Lanthanum Nickelate Nanofibers for High Energy Density Supercapacitors

Abstract

The series LaxSr1−xNiO3−δ (0.3≤x≤1) nanofibers (LNF-x) samples are prepared by using electrospun method. We investigate the structure and the electrochemical properties of LNF-x in detail. As a result, LNF-x nanofibers present a perovskite structure, and the LNF-0.7 sample with high specific surface area display remarkable performance as an electrode material for supercapacitors. The maximum specific capacitance value of 719F·g−1 at a current density of 2A·g−1, which retains 505F·g−1 at a high current density of 20A·g−1, is obtained for LNF-0.7 electrode in 1M Na2SO4 aqueous electrolyte. Moreover, the LNF-0.7//LNF-0.7 symmetric supercapacitor device using 1M Na2SO4 aqueous solution is successfully demonstrated. The capacitor device can operate at a cell voltage as high as 2V, and it exhibits an energy density of 30.5Wh·kg−1 at a high power density of 10kW·kg−1 and a high energy density of 81.4Wh·kg−1 at a low power density of 500W·kg−1. More importantly, this symmetric supercapacitor also shows an excellent cycling performance with 90% specific capacitance retention after 2000 charging and discharging cycles. Those results offer a suitable design of electrode materials for high-performance supercapacitors.