Double-Layer N,S-Codoped Carbon Protection of MnS Nanoparticles Enabling Ultralong-Life and High-Rate Lithium Ion Storage

The rational synthesis of transition metal sulfides with long cycle life and good rate performance is essential for building superior electrochemical energy storage devices. In this work, the MnS nanoparticles/N,S-codoping carbon nanotubes (MnS@N,S-C NTs) with double-layer carbon have been synthesized through a facile in situ transformation method. The synergetic coupling effects benefited from the advantages of double N,S-C layers, and porous structures are effective to allow fast electrons/lithium ions transport and keep good structural integrity during the charging/discharging process. Owing to the large surface area, the MnS@N,S-C NTs electrode is mainly pseudocapacitive in nature during the charge–discharge process, which is beneficial to enhance the electrochemical transfer kinetics. When used as anodes for lithium ion batteries, the MnS@N,S-C NTs exhibit a high specific capacity of 796 mAh g–1 during the 200th cycle at 1.0 A g–1. Even at 10.0 A g–1, the discharge specific capacity of the MnS@N,S-C NTs can still reach about 400 mAh g–1 during the 9000th cycle with superior rate capability. The proposed approach may promote rational creation of other hybrid functional materials for energy storage and conversion.