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

摘要

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.