Multi-walled carbon nanotube interlayers with controllable thicknesses for high-capacity and long-life lithium metal anodes

Lithium metal is one of the most exceptional anode materials for the next-generation rechargeable batteries because of its ultrahigh theoretical specific capacity and lowest reduction potential. Unfortunately, low Coulombic efficiency, poor cycling lifespan and short-circuiting-related safety issues due to the uncontrolled growth of lithium dendrites during battery cycling have hindered practical applications of rechargeable lithium-metal batteries. Herein, we report an efficient strategy to overcome these shortcomings by using a multi-walled carbon nanotube interlayer film with controllable thickness between lithium anode and a separator. Lithium electrodes with added interlayers can stabilize the cycling of symmetrical cells up to 600 h at 3 mA h cm−2 capacity and 5 mA cm−2 current density and up to 180 h at 5 mA h cm−2 capacity and 10 mA cm−2 current density, respectively, without any signs of short circuits. The volume expansion is significantly mitigated by the interlayer during cycling. Using lithium anode with interlayer, we achieve excellent Coulombic efficiency, superior capacity retention and small polarization for lithium-oxygen battery and lithium-lithium cobalt oxide/lithium iron phosphate batteries. These interlayers, produced using low-cost raw materials and simple methods, have a promising potential for realization of high-capacity, dendrite-free and long-life lithium metal anodes for the large-scale production.