Encapsulating Co8FeS8 nanoparticles in N-doped carbon tubes/carbon structure for high-performance lithium storage

•Co8FeS8 nanoparticles encapsulated in NCTs@C structure are prepared.•NCTs@C ensures even dispersion of Co8FeS8 and fast transport of electron and ion.•Co8FeS8/NCTs@C exhibits excellent rate capability and cycling performance. In this study, composites with Co8FeS8 nanoparticles encapsulated in N-doped carbon tubes/carbon structure (Co8FeS8/NCTs@C) were developed, wherein NCTs and C serve as supporting carrier and surface coating layer, respectively. The synergistic effect of NCTs and C effectively avoids aggregation of Co8FeS8 nanoparticles, improves the conductivity and ensures the integrity of electrodes during cycling. Therefore, Co8FeS8/NCTs@C shows excellent performance as anode of Li-ion batteries. Their specific capacities at 0.1, 0.2, 0.3, 0.5, 1.0 and 2.0 A·g−1 are 1002, 871, 822, 760, 678 and 602 mAh·g−1, respectively. Moreover, the specific capacities are 1032 mAh·g−1 at 0.3 A·g−1 after 140 cycles and 878 mAh·g−1 at 1.0 A·g−1 after 300 cycles.