In Situ Synthesis of Porous SnO2/SnS2@PC Anode Material with High Capacity Using Calcium Carbonate as Template for Lithium-Ion Batteries

Tin-based materials have emerged as promising anode candidates for advanced lithium-ion batteries (LIBs) due to their high theoretical capacity (e.g., 994 mAh·g−1 for Li4.4Sn), moderate operating potential, and natural abundance. However, Tin-based materials suffer from severe volume expansion (>300%) and rapid capacity decay during cycling. To mitigate these challenges, a composite composed of tin-based materials and porous carbon (PC), i.e., SnO2/SnS2@PC, was prepared by calcining a mixture of SnO2, petroleum asphalt and calcium carbonate at high temperature, where petroleum asphalt acted as the carbon and sulfur resource, and calcium carbonate acted as a pore-forming template. The prepared SnO2/SnS2@PC composite had a specific surface area of 190 m2·g−1 with total pore volume 0.386 cm3·g−1, and delivered an initial specific capacity of 1431 mAh·g−1 and retained 722 mAh·g−1 at 100th cycle at 0.2 A·g−1, which is nearly three folds that of the actual capacity (~260 mAh·g−1) of commercial graphite. The novelty of this work lies in that the abundant sulfur element in petroleum asphalt was fully utilized to react in situ with nano SnO2 to generate SnS2 and form a composite with high specific capacity and good structural stability, along with greatly reducing the emission of the harmful element sulfur into the atmosphere.