Pristine Ni-Sn layered-double-hydroxide and NiO/SnO₂ hierarchical nanocomposites as high-performance electrode materials for supercapacitor applications

• Metal oxide nanocomposite in LDH forms for high performance super capacitor application. • LDH nanocomposites with structural integrity, superior dielectric properties, and energy-efficient low dielectric loss. • High aspect ratio and high ionic conductivity NiO/SnO 2 TMO exhibit superior specific capacitance of 821 F/g at a 5 mV/s. • Energy storage process of the prepared NiO/SnO 2 nanocomposites is examined via Trasatti method. • R 2 = 0.98 for anodic peak is confirming their excellent reversibility. Cost effective and complication-free wet chemical co precipitation protocal was employed to prepar Ni-Sn-layered double hydroxide and NiO/SnO 2 nanocomposites. Fundamental characterizations were done to evaluate structural, optical, morphological and dielectric behaviors. Cubic and tetragonal structures were witnessed for NiO and SnO 2 via XRD analysis respectively. Allowed direct band gap nature was revealed from the optical absorption study and the calculated bandgap values were 3.29, 3.39, 3.09 and 3.20 eV for NiO. SnO 2 , NiO/SnO 2 , and Ni-Sn-LDH respectively. Surface features, stacked layered nanosheet arrangements and textural properties of the high-performance electrode materials were witnessed from SEM and HRTEM analyses. The composite materials, NiO/SnO 2 and Ni-Sn-LDH nanosheet, demonstrate an enhanced capacitance per unit area and superior capacitance retainable nature with numerical values of 821 F/g for 5mV/s scanning for NiO/SnO 2 sample. For 1 ampere per gram electric current density NiO/SnO 2 exhibited a capacitance of 99.2% retentively beyond 300 consecutive cycles. High surface area and large active site densities of this electrode material enabled it to exhibit such performance with respect to charge storage, enhanced charge/discharge rates and long-term stability. The Ni-Sn-LDH electrode exhibited 315 F/g of capacitance per unit area at 5 mV/s scan rate. Appreciable retentive capacitance (98.01%) and one ampere per gram beyond 300 cycles was shown by Ni-Sn LDH. Morphological dependent (granular structured layers) carbon-free stain less steel electrode supercapacitance properties were revealed from the present work.