Sodium Insertion into Tin Cobalt Carbon Active/Inactive Nanocomposite

Sodium insertion into nanostructured (Sn0.5Co0.5)1-xCx, (0.2 ≤ x ≤ 1), was investigated. This is the first report to our knowledge of an active/inactive alloy with tin being used for sodium-ion batteries. Although the cycle life of the alloy is superior to pure tin, the capacity obtained was low, compared to lithium insertion into the same material. It was found that only 8% of the tin in (Sn0.5Co0.5)1-xCx is active at 30°C, while 38% of the Sn is active at 60°C. The carbon phase in (Sn0.5Co0.5)1-xCx was found to have a capacity of about 130 mAh/g below 1.2 V and was 100% active at all temperatures measured.