Improving the electrochemical performance of silicon materials by SnO2 through structural design and conductivity

The Si material of the highest theoretical capacity (4200 mAh.g−1) cannot be commercially applied in real life owing to its vast volume expansion during the charge–discharge process and low electrical conductivity. Here, we introduce a [email protected]2 material with a coating structure, in which SnO2 is coated on the surface of the silicon material. The coating structure can effectively alleviate the volume expansion stress of the silicon material. The Sn produced by the reaction of SnO2 with Li during the first cycle has good conductivity, thereby improving the electrochemical performance of the silicon material. The electrochemical performance of the material is excellent. At the current density of 0.2A.g−1, the first coulombic efficiency of the battery reaches 84.1%, and the specific discharge capacity of the battery can be reached at 1926mAh.g−1 after 200 cycles.