Boron-doping induced lithophilic transition of graphene for dendrite-free lithium growth

Abstract Li metal, possessing advantages of high theoretical specific capacity and low electrochemical potential, is regarded as the most promising anode material for next-generation batteries. However, despite decades of intensive research, its practical application is still hindered by safety hazard and low Coulombic efficiency, which is primarily caused by dendritic Li deposition. To address this issue, restraining dendrite growth at the nucleation stage is deemed as the most effective method. By utilizing the difference of electronegativity between boron atoms and carbon atoms, carbon atoms around boron atoms in boron-doped graphene (BG) turn into lithiophilic sites, which can enhance the adsorption capacity to Li+ at the nucleation stage. Consequently, an ultralow overpotential of 10 mV at a current density of 0.5 mA/cm2 and a high average Coulombic efficiency of 98.54% over more than 140 cycles with an areal capacity of 2 mAh/cm2 at a current density of 1 mA/cm2 were achieved. BG-Li|LiFePO4 full cells delivered a long lifespan of 480 cycles at 0.5 C and excellent rate capability. This work provides a novel method for rational design of dendrite-free Li metal batteries by regulating nucleation process.