Rational Design\nof Quasi-1D Multicore–Shell\nMnSe@N-Doped Carbon Nanorods as High-Performance Anode Material for\nSodium-Ion Batteries

Sodium-ion batteries (SIBs) are considered one of the\npromising\ncandidates for energy storage devices due to the low cost and low\nredox potential of sodium. However, their implementation is hindered\nby sluggish kinetics and rapid capacity decay caused by inferior conductivity,\nlattice deterioration, and volume changes of conversion-type anode\nmaterials. Herein, we report the design of a multicore–shell\nanode material based on manganese selenide (MnSe) nanoparticle encapsulated\nN-doped carbon (MnSe@NC) nanorods. Benefiting from the conductive\nmulticore–shell structure, the MnSe@NC anodes displayed prominent\nrate capability (152.7 mA h g<sup>–1</sup> at 5 A g<sup>–1</sup>) and long lifespan (132.7 mA h g<sup>–1</sup> after 2000\ncycles at 5 A g<sup>–1</sup>), verifying the essence of reasonable\nanode construction for high-performance SIBs. Systematic <i>in\nsitu</i> microscopic and spectroscopic methods revealed a highly\nreversible conversion reaction mechanism of MnSe@NC. Our study proposes\na promising route toward developing advanced transition metal selenide\nanodes and comprehending electrochemical reaction mechanisms toward\nhigh-performance SIBs.