Exploring SnS nanoparticles interpenetrated with high concentration nitrogen-doped-carbon as anodes for sodium ion batteries

Abstract

Cyanide based ionic liquid derived nitrogen-doped-carbons (N-C) has been demonstrated to be fascinating conductive coating agents to improve the performance of lithium ion battery electrodes. To explore its role in electrodes of sodium ion batteries (SIBs), SnS nanoparticles interpenetrated with a high concentration of such N-C ((hN-C@SnS)) are synthesized and comprehensively investigated as anodes for SIBs. We demonstrate that hN-C@SnS electrode can exhibit a remarkable cycling stability as well as a promising rate capability. Especially, the role of cyanide based ionic liquid derived N-C in a sodium ion battery electrode is systematically investigated for the first time by a series of characterization techniques, concluding that the superior cell performance are mainly benefiting from the homogeneous interpenetration of N-C as effective conductive network, rather than its advantageous role in Na+ storage and electron transport. In addition, ex situ XPS measurements strongly suggest that the conversion step of SnS is irreversible, while the alloying process to NaxSn is mostly reversible, which is in strong contrast with previous reports.