A potential pyrrhotite (Fe7S8) anode material for lithium storage

Abstract

Fe₇S₈@C nanospheres were prepared by a simple solid–solid reaction and showed a high specific capacity and an excellent high rate performance as the anode material in lithium ion batteries. The core–shell Fe₇S₈@C composites delivered a very high reversible capacity of 695 mA h g⁻¹ at 0.1 A g⁻¹ after 50 cycles between 0.01 and 3.00 V. The Fe₇S₈@C composites also showed a discharge plateau at 1.5 V, cycling between 1.20 and 2.50 V, and exhibited a specific capacity of 397 mA h g⁻¹ at 0.1 A g⁻¹ over 200 cycles, which is higher than the theoretical capacity of Li₄Ti₅O₁₂ (about 175 mA h g⁻¹).