5 at.%-vanadium hybriding enables silicon anode with high initial coulombic efficiency and low internal stress

Silicon anodes are promising for high-energy-density lithium-ion batteries. Nevertheless, unsatisfied initial Coulombic efficiency (ICE) and structure collapse are two barriers still hindering their application. Here, we report a 5 at%-vanadium hybriding strategy to stabilize Si film anode to deliver a high initial Coulombic efficiency of 92.1% with a discharge capacity of 2434.9 mAh g^-1 and a desirable capacity retention of 80% after 100 cycles at 1 A g^-1. Physical and electrochemical analysis demonstrates the Li<em>_x</em>PO_yF_z-rich inorganic SEI and the low film internal strain are two advantageous factors for the desirable Li-ion storage reversibility and stability. A full battery with a LiFePO₄ cathode delivers energy densities of 291.9 and 194.6 Wh kg^-1 under power densities of 145.9 and 389.2 W kg^-1, respectively. This result on Si anodes may pave the way to next-generation high-energy-density lithium-ion batteries.