"Mechanical-electrochemical" coupling structure and the application as a three-dimensional current collector for lithium metal anode

To construct a lithiophilic-lithiophobic gradient collector has been regarded as an effective strategy to address the challenge of lithium dendrite growth in Li metal anode. However, it was also found that the uneven stress accumulation, induced by the directional deposition, would cause fatigue-like failure in the gradient structure. In this work, a hybrid carbon nano fiber (CNF) structure, consisting of a gradient nitrogen doping CNF layer and a Cu doped CNF layer, was fabricated. The Cu-decorated carbon nanofibers not only provide a deposits-free (lithiophilic) surface, but also act as "reinforcing rib" to resist the fatigue stress. The unique hybrid structure delivered a high Coulomb efficiency and resistance to repeat stress application.