Lithium-ions uptake by MAX/graphene hybrid

Abstract

Combining nanoparticles in well-designed architecture with complementary properties is an attractive strategy used for developing multi-functional, high-performance materials. Herein, to explore the mechanism of Li-ions uptake and storage potential of layered ternary carbides (MAX phases), we report on the Ti2SC and Ti3SiC2 with two-dimensional (2D)-reduced graphene oxide (rGO) that electrically connects MAX phase particles. The heterostructure formation was achieved through in-situ wet chemical processing. The method efficiently prevented restacking of rGO nanosheets, aggregation of MAX particles, and generated a porous heterostructure permeable for electrolyte. This facilitated the electrolyte transport and the access of ions to the electrode. In addition, there was a strong coupling effect between MAX phase compound and rGO in these hybrids. When tested as anodes for Li-ion batteries, the hybrids displayed high reversible capacity, very good rate performance, and excellent cycling stability. Specifically, the capacity of in-situ synthesized Ti2SC/rGO hybrid showed an increasing trend during cycling. After a few initial cycles, 576 mAh·g−1 was achieved after 500 charge/discharge cycles with a current of 400 mA·g−1. This work further demonstrates the Li-ion storage potential of MAX phases and suggests the need for further exploration of this large family of layered materials.Graphical abstract