RESUMO
Cobalt sulfide and molybdenum sulfide, with high theoretical capacities, have been considered as one of most promising anode materials for lithium-ion batteries (LIBs). However, the poor cyclability and low rate performances originating from the large volume expansion and poor electrical conductivity extremely inhibit their practical application. Here, the electrochemical performances are effectively improved by growing amorphous cobalt sulfide and molybdenum sulfide onto amorphous carbon-coated multiwalled carbon nanotubes (CNTs@C@CoS2 and CNTs@C@MoS2 ). The CNTs@C@CoS2 presents a high reversible specific capacity of 1252â mAh g-1 at 0.2â Ag-1 , excellent rate performance of 672â mAh g-1 (5â Ag-1 ), and enhanced cycle life of 598â mAh g-1 after 500 cycles at 2â Ag-1 . For CNTs@C@MoS2 , it exhibits a specific capacity of 1395â mAh g-1 , superior rate performance of 727â mAh g-1 at 5â Ag-1 , and long cycle stability (796â mAh g-1 after 500 cycles at 2â Ag-1 ). The enhanced electrochemical properties of the electrodes are probably ascribed to their amorphous nature, the combination of CNTs@C that adhered and hindered the agglomeration of CoS2 and MoS2 as well as the enhanced electronic conductivity.