Nanoscale α-MnS crystallites grown on N-S co-doped rGO as a long-life and high-capacity anode material of Li-ion batteries

Highlights: • Nanoscale α-MnS cystallites grown on N-S co-doped rGO was prepared. • Honeycomb-like α-MnS/NSG composites exhibit long-life and super-stable cyclability. • The α-MnS/NSG electrodes show superior cyclability at asymmetric current densities. • The chemical bonds combination plays a significant role in structural stability. - Abstract: The rock-salt structural manganous sulfide (α-MnS) is of higher lithium storage capacity. To improve the cyclability of α-MnS anode in lithium-ion batteries, we prepared a composite of α-MnS nanocrystallites grown on nitrogen and sulfur co-doped reduced graphene oxide (rGO) honeycomb framework. N and S atoms have been co-doped into rGO along with the growth of the α-MnS nanocystallites by a one-pot hydrothermal synthesis using thiourea as dopant and reactant. The typical α-MnS/N−S co-doped rGO (NSG) composite electrode exhibits a reversible capacity as high as 763.5 mAh g⁻¹ after 100 cycles at 100 mA g⁻¹, and a reversible capacity of 576.7 mAh g⁻¹ even after 2000 cycles at 1000 mA g⁻¹. More importantly, the α-MnS/NSG composite electrodes show superior cycle performance at asymmetric discharge/charge current densities. The excellent electrochemical performance can be attributed to that the α-MnS nanocrystallites shorten lithium ion transmission distance, N-S co-doping improves the electronic conductivity of rGO, and the formation of chemical bonds combination between α-MnS and NSG enhances the electrode structural stability and the electron transport. In addition, more stable architecture of NSG-supported ultrafine α-MnS particles is formed upon cycling, which greatly enhances the electrical contact and further improves the electrochemical performance.