Sulfur and nitrogen codoped Nb2C MXene for dendrite-free lithium metal battery

• S and N codoped Nb 2 C MXene for stable Li metal cell has been made. • Codoped Nb 2 C attracts Li greatly, with good electroconductivity and numerous active sites. • The modified Cu shows excellent electrochemical performance like high CE, long lifespan, etc. Lithium (Li) metal is considered as a promising anode for next-generation energy storage systems, but uncontrollable dendrite and low Coulombic efficiency (CE) impede their commercialization. Herein, by confining Li into sulfur and nitrogen codoped Nb 2 C MXene, a more practical Li anode with high performance has been synthesized. S and N doping sites serve as extrinsic defects and active sites for reaction, as well as enhance its electroconductivity. Compared with undoped Nb 2 C, N and S codoped Nb 2 C is more lithiophilic with synergistic effect, as verified by both density functional theory (DFT) calculation and electrochemcial experiments. Hence, the codoped Nb 2 C can be used as three dimensional (3D) lithiophilic and conductive host, guiding hostless Li metal to nucleate and plate uniformly. Moreover, the introduction of heteroatoms can broaden the interlayer spacing and stabilize the structure of MXene, avoiding its pulverization and restacking during cycling. As a result, the as-developed Li metal anodes are armed with strong dendrite inhibiting ability and show excellent electrochemical performance, such as high CE, long lifespan and prominent practical performance in full cell. The codoped Nb 2 C MXene can provide a new avenue for the development of alkali metal batteries and shed light on the research of suppressing dendrite growth.