Graphene nanoscroll/nanosheet aerogels with confined SnS2 nanosheets: simultaneous wrapping and bridging for high-performance lithium-ion battery anodes

摘要

In this paper, we report graphene nanoscrolls bridged by crumpled graphene nanosheets as an effective conductive framework for confining SnS2 nanosheets for lithium-ion battery (LIB) applications. The nanoscroll/nanosheet hybrid aerogels (GNAs) with confined SnS2 nanosheets are facilely prepared via fast quenching, freeze-drying and thermal annealing. During quenching, wrapping SnS2 nanosheets in the nanoscrolls and bridging the one-dimensional nanoscrolls by the two-dimensional nanosheets occur simultaneously, and the ratio of nanoscrolls/nanosheets can be controlled by simply adjusting quenching conditions. The optimized SnS2/GNA is highly porous with a large specific surface area of 127.1 m(2) g(-1) and multi-scale pore structure, which can effectively prevent SnS2 aggregation to provide abundant lithiation/delithiation sites, and buffer volumetric change and pulverization of SnS2 nanosheets. Moreover, the three-dimensional conductive network formed in the hybrid aerogels can remarkably improve its electrical conductivity while providing sufficient channels for the transportation of lithium ions and charges. As a result, the optimized SnS2/GNA nanocomposite exhibits enhanced electrochemical performance with a high initial reversible capacity (1514.8 mAh g(-1) at 0.1 A g(-1)), excellent rate capacity (665.4 mAh g(-1) at 5 A g(-1)) and good cyclic stability (1050 mA h g(-1) at the 50th cycle). This may provide an efficient generic approach for encapsulation of transition metal dichalcogenide materials in conductive nano/micro confined spaces for fabrication of high-performance LIB anodes. (C) 2018 Elsevier Ltd. All rights reserved.