Ultrathin Ni_1−xCo_xS₂ nanoflakes as high energy density electrode materials for asymmetric supercapacitors

Abstract

Transition metal compounds such as nickel cobalt sulfides (Ni–Co–S) are promising electrode materials for energy storage devices such as supercapacitors owing to their high electrochemical performance and good electrical conductivity. Developing ultrathin nanostructured materials is critical to achieving high electrochemical performance, because they possess rich active sites for electrochemical reactions, shortening the transport path of ions in the electrolyte during the charge/discharge processes. This paper describes the synthesis of ultrathin (around 10 nm) flower-like Ni1− xCoxS2 nanoflakes by using templated NiCo oxides. The as-prepared Ni1− xCoxS2 material retained the morphology of the initial NiCo oxide material and exhibited a much improved electrochemical performance. The Ni1− xCoxS2 electrode material exhibited a maximum specific capacity of 1066.8 F·g−1 (533.4 C·g−1) at 0.5 A·g−1 and a capacity retention of 63.4% at 20 A·g−1 in an asymmetric supercapacitor (ASC). The ASC showed a superior energy density of 100.5 Wh·kg−1 (at a power density of 1.5 kW·kg−1), an ultrahigh power density of 30 kW·kg−1 (at an energy density of 67.5 Wh·kg−1) and excellent cycling stability. This approach can be a low-cost way to mass-produce high-performance electrode materials for supercapacitors.

DFT-aided experimental investigation on the electrochemical performance of hetero-interface-functionalized CuO nanoparticle-decorated MoS2 nanoflowers for energy storage applications

“…Electrochemical energy storage materials and technologies have drawn significant research attention due to the growing demand for effective, eco-friendly, and renewable energy sources. [1][2][3] Batteries and electrochemical capacitors are primarily used for energy storage applications. Among them, electrochemical capacitors have gained tremendous interest due to their excellent capacitance, cyclic capacity, and low internal resistance, energy density, and power density.…”

Tremella-like 2D Nickel–Copper Disulfide with Ultrahigh Capacity and Cyclic Retention for Hybrid Supercapacitors

“…Ni x Co 1−x S 2 presents a specific capacitance of 1698 F g −1 at 2 A g −1 . Wang et al 19 proposed that flower-like Ni 1−x Co x S 2 originated from NiCo oxides. The Ni 1−x Co x S 2 electrode displays an elevated specific capacitance of 1066.8 F g −1 at 0.5 A g −1 .…”