Synergistic modulation of Li nucleation/growth enabled by CNTs-wrapped lithiophilic CoP/Co2P decorated hollow carbon polyhedron host for stable lithium metal anodes

Infinite volume expansion and uncontrolled lithium dendrite growth are the main bottlenecks that greatly hinder the commercial application of lithium metal anodes. Herein, derived from zeolitic imidazolate framework (ZIF)-67, carbon nanotubes (CNTs)-wrapped and CoP/Co2P uniformly distributed nitrogen-doped hollow porous polyhedron carbon (CNT-CoP@NC) is elaborately designed as lithium metal host. A hybrid of N-doping and metallic phosphides modifications improves the lithiophilicity and reduces the nucleation barrier, consequently leading to homogeneous nucleation and smooth deposition of metallic lithium, thus suppresses the growth of Li dendrites. Meanwhile, self-generated CNTs arrays efficiently reduce the local current density. Moreover, the reduced lithium is preferentially deposited into the hollow structure of CNT-CoP@NC and then filled the voids among the CNT-CoP@NC particles. This all-pervasive Li plating design can not only alleviate the volume effect, but also maximize the anode space utilization. Benefiting from these synergistic modulations, even with an ultra-thin (7.2 mu m) anode layer of CNT-CoP@NC host, a high Coulombic efficiency for more than 400 cycles and an extended lifespan of 1,700 h under 1 mA.cm(-2) can be achieved. When paired with a competitive high mass loading (17.1 mg.cm(-2)) LiFePO4 cathode, a superb cycling stability (126.7 mAh & BULL;g(-1) over 550 cycles) is recorded at 1 C.

Automated summary

Infinite volume expansion and uncontrolled lithium dendrite growth are the main obstacles for the commercial application of lithium metal anodes. A novel lithium metal host, CNT-CoP@NC, derived from ZIF-67, is designed to improve lithiophilicity and reduce nucleation barrier, leading to homogeneous nucleation and smooth deposition of metallic lithium, thus suppressing dendrite growth. Furthermore, self-generated CNTs arrays reduce local current density and the hollow structure of CNT-CoP@NC enhances anode space utilization. With these modifications, a high Coulombic efficiency for more than 400 cycles and an extended lifespan of 1,700 hours are achieved, indicating the great potential of this design for practical applications.