High-Capacity, High-Rate Bi-Sb Alloy Anodes for Lithium-Ion and Sodium-Ion Batteries

Homogeneous alloys consisting of Bi and Sb have been fabricated by a facile high-energy mechanical milling with carbon and evaluated as potential anode materials in both lithium-ion and sodium-ion batteries. Specifically, Bi0.57Sb0.43-C and Bi0.36Sb0.64-C have been made, and they exhibit electrochemical performances superior to those of their counterparts Bi-C and Sb-C. For example, the Bi0.57Sb0.43-C sample delivers an initial delithiation capacity of 410 mA hg(-1) and cycles stably for 300 cycles with a capacity decay of 0:09% per cycle at a current density of 200 mA g(-1). It also exhibits high rate capacities in cells: 355 mA h g(-1) at 5C current and 326 mA h g(-1) at 7.8C current. in the case of a sodium-ion cell, its initial desodiation capacity is 375 inA h g(-1) with a capacity retention of 78% at the 50th cycle. At a high current rate of 2.6C (1000 mA h g(-1)), it still delivers a desodiation capacity of 326 mA h g(-1).