Regulating Li nucleation/growth via implanting lithiophilic seeds onto flexible scaffolds enables highly stable Li metal anode

2021 
Abstract Lithium (Li) metal is deemed as an ideal and promising star anode for high energy storage but its application still is impeded due to uncontrollable Li dendrite growth and tremendous dimension change. Although the flexible and conductive three-dimensional (3D) skeleton can improve the structural and interfacial stability of Li anode, its inherently lithiophobic feature usually brings a high nucleation barrier, uneven Li+ flux, and large concentration polarization, leading to inhomogeneous Li plating/stripping. Here, we develop target material (denoted as Mo2C NPs@CC) consisting of well-distributed molybdenum carbide nanoparticles (Mo2C NPs) with intrinsic lithiophilicity serving as lithiophilic seeds implanted onto the carbon cloth, breaking the dilemma of ordinary 3D conductive skeletons. The Mo2C NPs with large Li absorption energy provide plentiful lithiophilic sites for guiding the uniform and thin Li-nuclei layer formation, thereby realizing flat Li growth and stable electrode/electrolyte interface. Moreover, the high electronic conductivity of Mo2C-modified 3D scaffolds can balance the lithiophilicity, ensuring the fast electron transport in the whole electrode, effectively lowering the local current density, and providing enough space for buffering volume change, and synergistically suppresses the growth of Li dendrites. As a result, a prolonged lifespan of 5000 cycles with low voltage hysteresis of 10 mV at current density of 2 mA cm-2 with area capacity (Ca) of 1 mA h cm-2 has been achieved, giving rational guidance for designing high-performance composite Li anodes.
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