Unveiling the high lithiophilicity of lithiated hard carbon for lithium metal battery anodes

Lithium metal batteries offer high theoretical capacity but suffer from dendrite growth and surface instability. In this study, composite electrodes are prepared by integrating lithium metal powder (LMP) with carbon hosts of varying graphitization degrees, including hard carbon (HC), soft carbon (SC), natural graphite (NG), and artificial graphite (AG). Among them, the LMP/HC electrode exhibits the best electrochemical performance, originating from the defect-rich nature of hard carbon, where abundant dangling-bond-associated sites serve as energetically favorable lithium adsorption and nucleation centers, enabling uniform lithium deposition. The LMP/HC_7DS electrode shows a remarkably low nucleation overpotential of 14.5 mV, compared to 239.0 mV for bare LMP, resulting in a prolonged cycle life of 1000 h versus 350 h for bare LMP in symmetric cells (1 mA/cm 2 , 1 mAh/cm 2 ). In full-cell tests at a 3C rate, LMP/HC_7DS retains 123.4 mAh/g with 98.6% capacity retention at the 1700th cycle, far outperforming bare LMP. While SC outperforms graphite-based hosts overall, it still lags behind HC. These findings demonstrate that lithium associated with defect sites or adsorbed on the surface of amorphous carbon enhances lithiophilicity, suppresses dendrite formation, and significantly improves the long-term stability of lithium metal batteries. • A lithium powder/lithiated hard carbon composite electrode has been fabricated. • Hard carbon was lithiated by mixing it with lithium powder, pressing, and shelving. • Lithiated hard carbon has stronger lithiophilicity than lithiated graphite. • Experimental results and DFT/MD calculations confirmed its strong lithiophilicity. • The composite electrode demonstrated excellent cycling stability.