Conformal coating of lithium-zinc alloy on 3D conducting scaffold for high areal capacity dendrite-free lithium metal batteries.

Li metal anode holds great promise to realize high-energy battery systems. However, the uncontrollable Li dendrites formation and infinite volume changes of Li severely hinder its practical applications. Herein, a 3D conductive carbon fibre with conformal lithiophilic Zn coating (CF@Zn) is developed to guide uniform Li plating/stripping and accommodate a large amount of Li metal. Phase evolution mechanism reveals that lithiated zinc (LiZn) alloy plays the real role in regulating the Li plating. Through the conformal incorporation of LiZn alloy, the Li affinity of carbon fibre has been improved significantly, which reduces the Li nucleation barrier and enables homogeneous Li nucleation and growth surround the carbon fibre, forming a conformal CF@LiZn@Li structure at initial stage. The 3D lithiophilic CF@LiZn scaffold with interconnected pores serves as robust host for high Li loading with small volume fluctuation, resulting in a dendrite-free Li metal battery with high areal capacity (up to 12 mAh cm−2). Moreover, the CF@LiZn electrode exhibits a high Coulombic efficiency of 97.1% at 5 mA cm−2, long cycle life of 280 cycles at 2 mA cm−2 and excellent rate performance (∼70 mV voltage hysteresis at 5 mA cm−2). Furthermore, excellent cyclability and rate performance are realized in full-cell batteries with CF@LiZn–Li anode and LiFePO 4 cathode. This work demonstrates a low-cost and lithiophilic alloy matrix for the fabrication of stable Li metal anode toward next-generation high-energy battery systems. A 3D conductive carbon fibre with conformal lithiophilic Zn coating (CF@Zn) is developed to guide uniform Li plating/stripping. Phase evolution mechanism reveals that lithiated zinc (LiZn) alloy plays the real role in regulating the Li plating. The 3D lithiophilic CF@LiZn scaffold serves as robust host for high Li loading with small volume fluctuation, resulting in a dendrite-free Li metal battery with high areal capacity, high Coulombic efficiency, long cycle life. [Display omitted] • A 3D conductive carbon fibre with conformal lithiophilic Zn coating (CF@Zn) is developed as the host material for Li metal. • Lithiated zinc (LiZn) alloy plays the real role in regulating the Li plating. • The 3D lithiophilic CF@LiZn scaffold enables a dendrite-free Li metal battery with high areal capacity and long cycle life. [ABSTRACT FROM AUTHOR]