A Three-Dimensional, Flexible Conductive Network Based on an MXene/Rubber Composite for Lithium Metal Anodes

Flexibility enhancement is a pressing issue in the current development of advanced lithium-metal battery applications. Many types of organic polymers are inherently flexible, which can form a composite structure enhancing electrode flexibility. However, organic polymers have a negative influence on the plating and stripping of lithium-metal anodes, and the large number of polymers block the pore of the material, reducing the utilization of the active site. Herein, we report a flexible porous substrate as an anode host based on a serine-modified three-dimensional structure of MXene and epoxidized natural rubber composite (3D/MXene-S-ENR), in which lithium ions can uniformly deposit in the interconnected pore structure. The 3D/MXene-S-ENR, having more nucleation sites, can effectively improve the uniformity of lithium metal, which effectively reduces the local current density and inhibits lithium dendrites. Compared with the serine-modified MXene and the epoxidized natural rubber electrode (MXene-S-ENR), the 3D/MXene-S-ENR electrode has lower overpotential and stable cycling. The lithium-sulfur batteries (Li-S) based on the 3D/MXene-S-ENR anode and sulfur cathode (3D/MXene-S-ENR@Li|S/C) deliver a stable discharge capacity of 316.2 mAh g^-1 after 350 cycles, with a Coulombic efficiency of 98.05%. Finally, we assembled a flexible pack battery, which demonstrates the potential value of the 3D/MXene-S-ENR anode in high-performance flexible lithium-sulfur batteries.