Synergy effect of regulated Li-plating and functional solid electrolyte interphase on graphite anodes

The growth of Li dendrites poses potential safety hazard to lithium-ion batteries (LIBs), and eliminating Li dendrites thoroughly stills face tough difficulties ahead. Thus, regulating Li-plating is a critical optimization-direction to address the issue. Herein, a “graphite-Li hybrid” anode with high reversibility is realized under the constant-capacity lithiation (CCL). Within CCL, the uniform distribution of Li-plating on the graphite surface is successfully achieved. The evolution in different states of solid electrolyte interphase (SEI) is investigated in detail to study the interaction between the potentials and impedance during the process of Li-intercalation and Li-deintercalation. Under the potential below 0 V and the state of charge (SOC) of 110% relative to the theoretical capacity, the F-rich SEI with high stability is constructed to hinder the emergency of Li dendrites and maintain the intact structure of graphite anode under long cycling. The cell presents more than 100% Coulombic efficiency (CE) with the 900 cycles, demonstrating the reversible Li-plating and the utilization of defects. And the CCL half-cell provides a good cycling performance and specific capacity of 900 cycles at 0.5 C, it is attributed to the synergy effect of stable inorganic-rich SEI and regulated active Li-plating.