Nitrogen-doped carbon coated zinc selenide nanoparticles derived from metal–organic frameworks as high-rate and long-life anode materials for half/full sodium-ion batteries†

To address the slow reaction kinetics and poor cycling stability of ZnSe during sodium storage, in this study, the two-dimensional network structure [Zn(L₃)·H₂O]_n (ZnL, L = 5-aminoisophthalic acid) was firstly successfully prepared by a simple solvothermal reaction. Then, nitrogen-doped carbon coated ZnSe nanoparticle composites (denoted as ZnSe@NC) were obtained by selenization of ZnL. Benefiting from the synergistic effect of ZnSe nanoparticles and NC, ZnSe@NC demonstrated ultra-long cycling stability (a capacity decay rate of only 0.052% per cycle) and high rate performance (400.6/311.1 mA h g⁻¹ at 0.1/10 A g⁻¹). The excellent electrochemical properties of ZnSe@NC can be attributed to high pseudocapacitance contribution, low charge transfer impedance, and high ion diffusion coefficient. In addition, ex situ XRD, XPS, and HRTEM analyses revealed that the sodium storage process of ZnSe@NC is a conversion reaction followed by an alloying reaction. More importantly, the sodium-ion full battery Na₃V₂(PO₄)₃@rGO//ZnSe@NC can maintain a reversible capacity of 216.4 mA h g⁻¹ after 100 cycles at 0.3 A g⁻¹. This approach provides a promising method for the design of MOF-derived metal selenide materials for energy storage and conversion.