Sandwich architecture of Sn[sbnd]SnSb alloy nanoparticles and N-doped reduced graphene oxide sheets as a high rate capability anode for lithium-ion batteries

Abstract

In this article, we report an active-matrix type SnSnSb alloy, which is sandwiched between nitrogen doped reduced graphene oxide (N-rGO) sheets in the form of a nanocomposite, as a high rate capability anode for lithium-ion batteries. The alloy nanocomposite is synthesized via a cheap and industrially scalable route of microwave-assisted hydrothermal synthesis, and is coated onto electrodeposited 3D microporous nickel foam current collector. The additional mechanical buffering, along with effective electron conduction and lithium ion diffusion pathways provided by N-rGO nanosheets and nickel foam, result in a specific capacity of ∼300 mAhg−1 at a specific current of 4 A g-1 by preventing both pulverization and delamination of the active material. This combination of properties in N-rGO decorated SnSnSb nanocomposite anode (with 40 wt% N-rGO) on nickel foam results in a 2nd cycle discharge specific capacity of 705 mAhg−1, with a stable reversible specific capacity of 500 mAhg−1 after 200 cycles @ 0.1 A g-1. The nanocomposite anode also shows capacity retention of 400 mAhg−1 @ 0.8 A g-1 (1C rate) for 120 cycles. As compared to low N-rGO (10 wt%) decorated nanocomposite, the high N-rGO (40 wt%) nanocomposite shows improved performance with a nominal sacrifice of capacity which is at par, if not superior, to the existing commercial graphitic anodes.