Trimetal NiCoMn sulfides cooperated with two-dimensional Ti3C2 for high performance hybrid supercapacitor

Abstract

Transition trimetallic sulfide NiCoMn–S attracts great attention due to its high specific capacity for hybrid supercapacitors, as well as Ti3C2 is considered essentially as a potential new electrode material with iconic two-dimensional layered structure and excellent conductivity. Herein, NiCoMn–S nanoparticles are composited with two-dimensional layered Ti3C2 via simple one-step hydrothermal method, which is first applied as positive electrode in hybrid supercapacitors (HSCs). A large number of NiCoMn–S nanoparticles distribute on the surface of Ti3C2 and even insert into the Ti3C2 layers, providing abundant electrochemical active sites for redox reaction and enhancing the mechanical stability for composites. Moreover, the NiCoMn–S/Ti3C2 composites show lower charge-transfer resistance than pure NiCoMn–S, illustrating that the two-dimensional layered structure of Ti3C2 improve the conductivity and supply additional electronic channels for ion transportation. The NiCoMn–S/Ti3C2-3.4% delivers a specific capacity of 347.1 ​C ​g−1 at a specific density of 1 ​A ​g−1, which is 28% higher than that of pure NiCoMn–S (270.2 ​C ​g−1 at 1 ​A ​g−1). Finally, a hybrid supercapacitor (HSC) is assembled by using NiCoMn–S/Ti3C2-3.4% as positive electrode and RGO as negative electrode, realizing a specific capacity of 164.3 ​C ​g−1 at 1 ​A ​g−1 and high specific energy of 16.2 ​Wh kg−1 at a specific power of 15 ​kW ​kg−1.