Electrochemical performance of A-site substituted SmSrNiO4_d for energy storage applications

In this work, a series of Ruddlesden popper oxide materials Sm1_xLaxSr1_xCaxNiO4_d (x = 0.00, 0.05, 0.10, 0.15, and 0.20) were synthesized and their electrochemical behavior was investigated in 1 M KOH alkaline solution. Phase formation in all the samples is confirmed through XRD. SEM depicts the porous morphology of all the samples. FTIR confirms the presence of -OOH and -OH groups in several compositions. The Cyclic voltammetry curve of Sm0.90La0.10Sr0.90Ca0.10NiO4_d and Sm0.80La0.20Sr0.80Ca0.20NiO4_d indicates the presence of the combination of both pseudo-capacitance and electrochemical doublelayer capacitance in these two electrodes. However, only the sample Sm0.90La0.10tSr0.90Ca0.10NiO4_d sample satisfies the condition of the general power law for pseudo capacitance. This material also shows the highest value of specific capacitance (910.20 F/g) and electrochemical double-layer capacitance (238.25 mF/cm2) among all the samples. XPS analysis reveals that oxidation states of the Nickel and Oxygen play a crucial role for the better electrochemical performance of the electrode. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.