Halloysite nanotubes favored facile deposition of nickel disulfide on NiMn oxides nanosheets for high-performance energy storage

Abstract

The exploitation of electrode materials is extremely important for electrochemical energy storage systems with high energy and power densities as well as long lifespan. Herein, a facile halloysite nanotubes (HNTs) assisting deposition method is developed to prepare nickel disulfide interconnected nanosheet arrays on nickel manganese oxides (Ni-Mn-O) as electrodes for battery-type supercapacitors, resulting in exceptional energy storage performance. Taking advantage of the unique tubular architecture of hollow HNTs, gradient deposition of NiS2 and Ni-Mn-O nanosheets on HNTs are realized with two-step in-situ hydrothermal reaction and sulfidation. HNTs not only favor the formation of NiS2 during sulfidation but also offer good porosity for electrochemical energy storage. In solution state, the hybrid electrode exhibits a high capacity (1144.7C g−1 at 1 A g−1 and 597.5C g−1 at 20 A g−1) with excellent cyclic stability (92.6% after 2000 cycles). Solid-state symmetric supercapacitors fabricated with NiS2@Ni-Mn-O/HNT hybrid demonstrate outstanding electrochemical performance for portable energy storage application. Our symmetric supercapacitors show a highest energy density of 164.2 Wh kg−1 at a power density of 1.3 kW kg−1. The energy density remains as high as 28 Wh kg−1 even at the highest power density of 15.1 kW kg−1 with good long-term cycling stability (90.5% after 2000 cycles).