A general synthesis of transition metal sulfide and nitrogen/sulfur co-doped three-dimensional graphene composite for high performance sodium storage.

The composite of carbon materials and transition metal sulfides can significantly improve the poor cycling performance of transition metal sulfides in sodium storage. In this study, the nitrogen/sulfur co-doped three-dimensional graphene (NSGN) encapsulating transition metal sulfides (FeS, Co 9 S 8 and Ni 3 S 2) are designed in a general method to improve the poor cycling stability of transition metal sulfides. The desired anode materials all show an excellent cyclic stability with the capacity retention of 63%, 97% and 98% after 100 cycles in sodium-ion batteries for FeS@NSGN, Co 9 S 8 @NSGN and Ni 3 S 2 @NSGN electrodes, respectively. Consequently, this work can provide a new insight for in-situ synthesis of metal sulfides and graphene composites to improve the performance of sodium storage. A simple method is used to synthesize transition metal sulfide and nitrogen sulfur Co-doped three-dimensional graphene composite, which shows excellent sodium storage performance. Unlabelled Image • Designing a general and simple method to synthesis MSs@NSGN composites. • MSs nanoparticles are wrapped by NSGN exhibit excellent structure stability. • MSs@NSGN electrodes exhibit good cycle stability and rate performance. [ABSTRACT FROM AUTHOR]