FeS2 hollow nanospheres as high-performance anode for sodium ion battery and their surface pseudocapacitive properties

In this work, hollow FeS2 nanospheres were successfully synthesized via a simple hydrolysis method followed by annealing and a sulfidation process. These nanospheres have diameters of approximately range from 300 to 400nm and shells about 50nm thick. Due to the unique hollow structures, these FeS2 reveal excellent long-cycling performance through improving the ratio of the pseudocapacitance effects in total charge storage. At a current density of 1Ag(-1), the FeS2 anode delivered a high capacity of 541.5mAhg(-1) after 100cycles. More importantly, these FeS2 could retain a capacity of 313.5mAhg(-1) after 500cycles at a high current density of 5Ag(-1), and still achieve a capacity of 147.2mAhg(-1) after 400cycles at a higher current density of 10Ag(-1).