Sb Doping and Amorphization Co‐Induced High Capacity and Excellent Durability of Tin Sulfide‐Based Anode for K‐Ion Batteries

Abstract The carbon nanotubes (CNTs) supported amorphous Sb doped substoichiometric tin dulfide (Sb─SnS x ) with a carbon coating (the C/Sb─SnS x @CNTs‐500) is reported to be an efficient anode material for K + storage. The formation of the C/Sb─SnS x @CNTs‐500 is simply achieved through the thermally induced desulfurization of tin sulfide via a controlled annealing of the C/Sb─SnS 2 @CNTs at 500 °C. When used for the K + storage, it can deliver stable reversible capacities of 406.5, 305.7, and 238.4 mAh g −1 at 0.1, 1.0, and 2.0 A g −1 , respectively, and shows no capacity drops when potassiated/depotassiated at 1.0 and 2.0 A g −1 for >3000 and 2400 cycles, respectively. Even at 10, 20, and 30 A g −1 , it can still deliver stable reversible capacities of 138.5, 85.1, and 73.8 mAh g −1 , respectively. The unique structure, which combines the advantageous features of carbon integration/coating, metal doping, and desulfurization‐induced amorphous structure, is the main origin of the high performance of the C/Sb─SnS x @CNTs‐500. Specifically, the carbon integration/coating can increase the electric conductivity and stability of the C/Sb─SnS x @CNTs‐500. The density function theory calculation indicates that the Sb doping and the desulfurization can facilitate the potassiation and increase the electric conductivity of Sb─SnS x . Additionally, the desulfurization can increase the K + diffusivity in Sb─SnS x .