3D hierarchical structure of MoS2@G-CNT combined with post-film annealing for enhanced lithium-ion storage

Abstract

We present a three-dimensional hierarchical structure of a ternary nanocomposite consisting of MoS2, graphite, and carbon nanotubes, as a new anode material for lithium-ion batteries. The 3D structure (3D MoS2@G-CNT), prepared by a simple and scalable high-energy ball milling process, contains 2D heterogeneous clusters between MoS2 and graphite, which are effectively interconnected by 1D carbon nanotubes. During the formation of 2D heterogeneous clusters, the surface area of MoS2 is significantly increased due to exfoliation driven by the solid lubrication effect from mechanical milling. The morphology and structural properties of 3D MoS2@G-CNT are analyzed by various techniques including XRD, Raman, SEM, TEM, and BET. At the optimal ratio of ingredients, 3D MoS2@G-CNT shows excellent electrochemical performance in terms of specific capacity, long-term cycle life, and rate capability. Specifically, at the best experimental conditions, 3D MoS2@G-CNT delivers similar to 1600 mAh g(-1) at 0.2 Ag-1 after 100 cycles and similar to 1200 mAh g(-1) at 0.5 Ag-1 after 450 cycles. To achieve these, we also introduce a post-film annealing step which induced rearrangement of the binder, thus improving the adhesion between the electrode material and current collector. Enhanced charge transport and mechanical integrity after this treatment are confirmed by FTIR, ex-situ SEM, and photographs. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.