Metal-organic framework derived CoSe2/N-doped carbon core-shell nanoparticles encapsulated in porous N-doped carbon nanotubes as high-performance anodes for sodium-ion batteries

Engineering ideal anode materials with low cost, considerable reaction kinetics and good structural stability are urgently needed for sodium-ion batteries (SIBs) toward large-scale applications. Here, a hierarchical peapod-like nanorod consisting of CoSe2/N-doped carbon (NC) core-shell nanoparticles (NPs) embedded into onedimensional (1D) N-doped carbon nanotubes (CoSe2/NC@NCNTs) with inner void space is developed and fabricated by a self-template, dopamine-coating, and succeeding selenization strategy. In the cleverly designed CoSe2/NC@NCNTs composite, the 1D peapod-like structure provides high mechanical strength and allows for fast mass transport/electron transfer. The external NCNTs and inner void space can effectively accommodate volumetric undulation and restrain the aggregation of CoSe2 NPs. Based on these advantages, the CoSe2/ NC@NCNTs electrode exhibits excellent comprehensive sodium storage performance, e.g., good rate capability (386.3 mAh g(-1) at 10.0 A g-1) and high cycling stability (394.2 mAh g(-1) up to 4500 loops at 5.0 A g(-1)). Moreover, the SIB full cells (Na3V2(PO4)(3)@C cathodes vs CoSe2/NC@NCNTs anodes) can achieve a reversible

Automated summary

A hierarchical peapod-like nanorod material was developed as an ideal anode material for sodium-ion batteries. It exhibits low cost, considerable reaction kinetics, and good structural stability, resulting in excellent energy storage performance.