LiF headspace affixed metallic Li composite enables Li accommodation on the anode surface with excellent electrochemical performance

Lithium (Li) metal composite with three-dimensional (3D) skeleton is regarded as the promising anode material for next generation rechargeable high energy batteries. Currently, most of the commercial cathodes are compounds rich of Li elements. In the initial operation of the as-assembled full cell, Li atoms are released from the cathode and directly deposited on the anode surface. The absence of the storage space in the conventional Li composite anode makes Li growth in an uncontrolled way and serious volume fluctuation of the electrode. Herein, LiF headspace affixed Li composite anode is prepared for the first time via a facile one-step thermal fusion method. The storage space constructed by LiF particles is formed on the top surface of 3D Li-LiZn-LiF (LZLF) composite anode, which can accommodate Li deposition from the cathode maintaining structural stability of the anode. Additionally, the LiF particles array on the surface can benefit for fast Li+ diffusion, suppressing Li dendrites growth and inducing uniform Li deposition. In a consequence, the LiF headspace affixed LZLF composite anode shows significantly improved electrochemical performance, i.e., more than 1000 h in symmetrical cell at 1 mA cm(-2) and 1 mAh cm(-2), or capacity retention of 88.9% after 800 cycles for the full cell at 1C with 2.45 mAh cm(-2) in carbonate ester-based electrolyte.

Automated summary

A lithium metal composite anode with a LiF headspace has been prepared via a one-step thermal fusion method. The LiF particles provide storage space for lithium deposition from the cathode, maintaining structural stability of the anode. The LiF particles on the surface facilitate fast Li+ diffusion, suppress lithium dendrite growth, and induce uniform lithium deposition. As a result, the LiF headspace affixed composite anode shows significantly improved electrochemical performance.