Design of coherent anode materials with 0D Ni3S2 nanoparticles self-assembled on 3D interconnected carbon networks for fast and reversible sodium storage

Abstract

There has been tremendous progress in development of nanomaterials for energy conversion and storage, with sodium-ion batteries (SIBs) attracting attention because of the high abundance of raw materials and low cost. However, inferior cycling stability, sluggish reaction kinetics, and poor reversibility hinder their practical applications. In the present study, Ni₃S₂/carbon nanocomposites with coherent nanostructures were successfully used as anodes in half- and full-cells. Outstanding cycling and rate performances are attributed to a synergistic effect between the Ni₃S₂ nanoparticles and interconnected carbon networks. The coherent porous framework effectively alleviated volume changes of Ni₃S₂, shortened the Na⁺ diffusion path, and accelerated electron transport and ionic diffusion during the electrochemical reaction. More importantly, conversion reaction products can be confined by the entangled carbon networks, leading to reversible redox reactions as demonstrated in ex situ XRD studies. The coherent Ni₃S₂/C nanocomposites demonstrated a highly reversible charge capacity of 453 and 430 mA h g⁻¹ at a current density of 0.1 and 0.4 A g⁻¹ over 100 cycles, respectively. At a current density of 2.0 A g⁻¹, high rate capacities of 408 mA h g⁻¹ can be attained over 200 cycles. The high performance of Na₃V₂(PO₄)₃/Ni₃S₂ full-cells enrich prospects for future practical applications.