Ni _1.5CoSe ₅ nanocubes embedded in 3D dual N-doped carbon network as advanced anode material in sodium-ion full cells with superior low-temperature and high-power properties

Abstract

An advanced anode for sodium-ion batteries is prepared by embedding cube-like Ni _1.5CoSe ₅ nanoaggregates into 3D dual N-doped carbon network.

Abstract

In this study, the double transition metal selenide Ni _1.5CoSe ₅ with cube-like nanoaggregate morphology was successfully embedded into a three-dimensional (3D) dual N-doped carbon network, developing an advanced anode material for sodium-ion batteries (SIBs). In the prepared composite, Ni _1.5CoSe ₅ nanoparticles were first coated by N-doped carbon (NC), which further aggregated to form nanocubes, and finally embedded into interconnected N-doped reduced graphene oxide (rGO) nanosheets; hence, the material was abbreviated as Ni _1.5CoSe ₅@NC@rGO. It delivered a reversible Na-storage capacity of 582.5 mA h g ⁻¹ at a low current density of 0.05 A g ⁻¹ and exhibited ultra-fast rate properties ( e.g., with the specific capacities of 180.8 and 96.3 mA h g ⁻¹ at high current densities of 30 and 50 A g ⁻¹, respectively). The much enhanced Na-storage properties were ascribed to the highly conductive 3D network constructed by dual N-doped carbonaceous materials, which acted not only as a highway for ultrafast charge transfer but also as an effective protector for the active Ni _1.5CoSe ₅ material and cube-like nanoaggregates with nanometer-sized primary particles. More significantly, the Ni _1.5CoSe ₅@NC@rGO electrode also exhibited superior energy storage performance in sodium-ion full cells when coupled with a high-voltage Na ₃V ₂(PO ₄) ₂O ₂F cathode, making it a promising anode material for practical SIBs.