A 3D Lithiophilic Mo<sub>2</sub> N-Modified Carbon Nanofiber Architecture for Dendrite-Free Lithium-Metal Anodes in a Full Cell.

Luo, Liu; Li, Jianyu; Yaghoobnejad Asl, Hooman; Manthiram, Arumugam · Adv Mater · 2019

basic_science · Level V

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Abstract

The pursuit for high-energy-density batteries has inspired the resurgence of metallic lithium (Li) as a promising anode, yet its practical viability is restricted by the uncontrollable Li dendrite growth and huge volume changes during repeated cycling. Herein, a new 3D framework configured with Mo<sub>2</sub> N-mofidied carbon nanofiber (CNF) architecture is established as a Li host via a facile fabrication method. The lithiophilic Mo<sub>2</sub> N acts as a homogeneously pre-planted seed with ultralow Li nucleation overpotential, thus spatially guiding a uniform Li nucleation and deposition in the matrix. The conductive CNF skeleton effectively homogenizes the current distribution and Li-ion flux, further suppressing Li-dendrite formation. As a result, the 3D hybrid Mo<sub>2</sub> N@CNF structure facilitates a dendrite-free morphology with greatly alleviated volume expansion, delivering a significantly improved Coulombic efficiency of ≈99.2% over 150 cycles at 4 mA cm<sup>-2</sup> . Symmetric cells with Mo<sub>2</sub> N@CNF substrates stably operate over 1500 h at 6 mA cm<sup>-2</sup> for 6 mA h cm<sup>-2</sup> . Furthermore, full cells paired with LiNi<sub>0.8</sub> Co<sub>0.1</sub> Mn<sub>0.1</sub> O<sub>2</sub> (NMC811) cathodes in conventional carbonate electrolytes achieve a remarkable capacity retention of 90% over 150 cycles. This work sheds new light on the facile design of 3D lithiophilic hosts for dendrite-free lithium-metal anodes.