Stabilizing Li metal anode by constructing lithiophilic N-doped carbon nanotubes on flexible carbon felt host

The Li metal anode is regarded as the most ideal anode material for the next-generation high-energy-density rechargeable Li batteries. Unfortunately, infinite volume change, “dead” Li formation, and continuous dendrite growth, severely hamper its commercial applications. Constructing 3D hosts has been widely developed to address these issues. Herein, nitrogen-doped carbon nanotubes (NCNTs) are grown in the carbon felt (CF) as the host material for Li metal anode via economic chemical vapor deposition was developed. Carbon felt provides a fast and uniform ion/electron pathway and alleviates the volume expansion during the charge/discharge process. With the introduction of NCNTs, lithiophilic functional groups like pyridine and pyrrole distributed uniformly on the surface of carbon felt, providing adequate lithiophilic sites to guide Li nucleation, ensuring the smooth Li deposition with dendrite-free morphology. As a result, excellent cycling stability is realized in symmetric cells with low overpotential and long lifespan. In addition, when the composite Li electrode is paired with the sulfur cathode (8.7 mg cm −2 ), the full cell displays a steady cycle life in coulombic efficiency retention of 93 % and a high specific capacity of 3.32 mAh cm −2 after 270 cycles at 0.2C. • The 3D free-standing composite scaffold with high N content of N-doped carbon nanotubes directly growing on the carbon felt was fabricated via the chemical vapor deposition method. • Lithiophilic functional groups such as pyridine and pyrrole distributed evenly on the carbon felt, offering adequate lithiophilic sites to regulate Li deposition. • The synergetic effect of increasing specific surface area and improving lithiophilicity can reduce the local current density and the nucleation barrier during Li replating. • The composite electrode employed in the Li anode realizes excellent electrochemical performance in symmetric cells and Li S full cells.