Coral-like a-MnS composites with N-doped carbon as anode materials for high-performance lithium-ion batteries

摘要

Coral-like a-MnS composites with nitrogen-doped carbon (NC) were designed as anode materials for lithium-ion batteries. A facile two-step method was developed to synthesize the composites. Hydrothermally obtained polyvinyl pyrrolidone (PVP) capped (NH4)2Mn2(SO4)3 was used as a precursor. The a-MnS-NC composites were attained by heating the precursor at different temperatures for an appropriate time in a N2 atmosphere. The microstructure and morphology were carefully investigated by means of field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and powder X-ray diffraction (XRD). As anode materials, the a-MnS-NC composites exhibit large reversible capacity, excellent cyclic stability and high rate capability. At a current density of 500 mA g~(-1), the discharge capacity reaches as high as 878 mA h g~(-1) at the first cycle and remains at 699 mA h g~(-1) even after 400 cycles.