Li migration, nucleation and growth behavior regulated by a lithiophilic cobalt phosphide-doped carbon nanofibers derived ion/electron conductive framework

The uncontrollable Li dendritic plating and infinite volumetric expansion significantly plague the practical applications of lithium (Li) metal, which is regarded as the most promising high-energy-density anode material for rechargeable batteries. The well regulated Li-ion (Li+) flux distribution and Li deposition is the prerequisite for feasible Li-metal batteries. In this work, the Li migration, nucleation and growth behavior are investigated with a lithiophilic CoP-doped carbon nanofibers ([email protected])-guided self-standing substrate. The high adsorption effect and low migration barrier of CoP to Li+ lead to the reversible conversion reaction between Li and CoP, enabling an even charge transportation and a homogeneous Li+ concentration gradient. The uniform nucleation and dense electrodeposition of Li over through the [email protected] is demonstrated via combined in-situ/ex-situ morphologic and electrochemical characterizations. Benefiting from the small nucleation and growth overpotential of Li, the symmetrical cell of [email protected]@Li can steadily operate under 0.5 mA cm−2 over 2000 h with a low voltage hysteresis of ca. 12 mV. When paired with a LiFePO4 cathode, a specific capacity exceeding 90 mAh g−1 up to 1000 cycles is achieved at 5 C (1 C = 170 mA g−1), demonstrating the dendritic Li suppression capability of the [email protected]@Li composite anode.