Cyanogel-Enabled Homogeneous Sb-Ni-C Ternary Framework Electrodes for Enhanced Sodium Storage.

Abstract

Antimony (Sb) represents an important high-capacity anode material for advanced sodium ion batteries, but its practical utilization has been primarily hampered by huge volume expansion-induced poor cycling life. The co-incorporation of transition-metal (M = Ni, Cu, Fe, etc.) and carbon components can synergistically buffer the volume change of the Sb component; however, these Sb-M-C ternary anodes often suffer from uneven distribution of Sb, M, and C components. Herein, we propose a general nanostructured gel-enabled methodology to synthesize homogeneous Sb-M-C ternary anodes for fully realizing the synergestic effects from M/C dual matrices. A cyano-bridged Sb(III)-Ni(II) coordination polymer gel (Sb-Ni cyanogel) has been synthesized and directly reduced to an Sb-Ni alloy framework (Sb-Ni framework). Moreover, graphene oxide (GO) can be in situ immobilized within the cyanogel framework, and after reduction, reduced graphene oxide (rGO) is uniformly distributed within the alloy framework, yielding a homogeneous rGO@Sb-Ni ternary framework. The rGO@Sb-Ni framework with optimal rGO content manifests a high reversible capacity of ∼468 mA h g^-1 at 1 A g^-1 and stable cycle life at 5 A g^-1 (∼210 mA h g^-1 after 500 cycles). The proposed cyanogel-enabled methodology may be extended to synthesize other homogeneous ternary framework materials for efficient energy storage and electrocatalysis.