Enhancing the cycling stability of Na-ion batteries by bonding SnS2 ultrafine nanocrystals on amino-functionalized graphene hybrid nanosheets†
Room-temperature Na-ion batteries (NIBs) have been generally expected to offer a hopeful perspective for renewable energy storage applications on a large scale. However, a shortage of appropriate anode materials for NIBs has hindered their large-scale applications. Here, we report the strong chemical bonding of tin sulfide on amino-functionalized graphene that is prepared by a facile amine-thermal reaction. In contrast to previous reports on graphene-based composite electrodes, our strategy has the following merits: the one-step formation of amino-functionalized reduced grapheme oxide (RGO) from GO and tight contact of SnS2 nanocrystals at an amino-functionalized graphene interface. This concept has been demonstrated by experimental results which are in congruence with first principles theoretical calculations. When investigated as an anode material for NIBs, the composite maintained a capacity of 680 mA h g−1 after cycling for 100 cycles at a current density of 200 mA g−1, and 480 mA h g−1 after 1000 cycles at 1 A g−1. The outstanding performance results from the unique structure of the hybrid nanosheets.