MnO@C nanorods derived from metal-organic frameworks as anode for superiorly stable and long-life sodium-ion batteries

Porous MnO@C nanorods were synthesized simply by annealing Mn-based metal-organic frameworks precursor. The morphology, structure and electrochemical performance of MnO@C hybrid were characterized by scanning electron microscopy, nitrogen adsorption/desorption isotherms, galvanostatic charge/discharge tests, cyclic voltammetry and electrochemical impendence spectroscopy. When used as anode material for sodium-ion batteries, the MnO@C hybrid exhibits a high reversible specific capacity of 260 mAh g⁻¹ after 100 cycles at a current density of 50 mA g⁻¹. When the current density is increased to 2 A g⁻¹, the MnO@C delivers a superior long-life cycling performance with a capacity of 140 mAh g⁻¹ at very high current density of 2 A g⁻¹. The excellent electrochemical performance of MnO@C can be attributed to its unique porous structure with MnO nanoparticles embedded in carbon matrix, which can apparently increase the electrical conductivity and buffer the volume change during the charge/discharge process.