Densified MoS2/Ti3C2 films with balanced porosity for ultrahigh volumetric capacity sodium-ion battery

Abstract

Developing high volumetric energy density sodium-ion batteries (SIBs) is indispensable for catering to the miniaturization and flexibility of various consumer electronics. Herein, we have reported the flexible and compact MoS2/Ti3C2 hybrid films with balanced porosity, where the few-layered MoS2 nanosheets are parallelly intercalated into the Ti3C2 interlayer space in virtue of strong electrostatic effect and difference in their sizes. The hybrid films have been stabilized by the two-dimensional (2D) confinement effect and the Ti-S-Mo bonds with a high density of ~2.9 g cm−3. Furthermore, the dual 2D compounds intrinsically possess satisfied ions conductivity, and meanwhile give rapid electrons transfer after assembling such superstructure. When directly used as SIB anode, the MoS2/Ti3C2 hybrid films deliver an exceptional volumetric specific capacity of 1510 mAh cm−3 at 0.28 mA cm−2 and 650 mAh cm−3 at 14 mA cm−2. The specific capacity remains unchanged after 300 cycles at 1.4 mA cm−2. More significantly, the areal specific capacity shows a linear relationship with the increase of film thickness from 9.6 to 43.1 μm without sacrificing the volumetric capacity. © 2020 Elsevier B.V.