Porous equipotential body with heterogeneous nucleation sites: A novel 3D composite current collector for lithium metal anode

Lithium metal is an ideal anode material for lithium battery thanks to its ultra-high specific capacity and lowest redox potential . However, uncontrollable growth of lithium dendrites hinders its application due to local aggregation of lithium ions and anisotropic growth of lithium metal driven by uneven electric field distribution. Here a strategy is proposed to address this issue via utilizing porous equipotential body decorated with heterogeneous nucleation sites as advanced three-dimensional current collector. The conductive network of carbon nanofibers is recognized as a porous equipotential body, where the interior electric filed is zero due to the well-defined electric field shielding effect. In addition, copper nanoparticles as heterogeneous nucleation sites are uniformly anchored on carbon nanofibers, which guide lithium deposition evenly. As a result, lower impedance and higher Coulombic efficiency (∼97%) are achieved in modified lithium-copper cell. In particular, the cycling lifetime of modified symmetric lithium-lithium cell is expanded up to 500 cycles at extremely large current density of 50 mA cm −2 .