3D Lithiophilic "Hairy" Si Nanowire Arrays @ Carbon Scaffold Favor a Flexible and Stable Lithium Composite Anode.

Abstract

Lithium metal anode is considered to be a promising candidate for high-energy-density lithium-based batteries. However, the safety issue induced by uncontrollable dendrite growth hinders the commercialization of a Li anode. Herein, self-supported three-dimensional flexible carbon cloth covered with a lithiophilic silicon nanowire array is constructed as the host for loading of molten Li to achieve the C/SiNW/Li composite anode. The electrode component of the carbon cloth provides the flexible and conductive substrate to accommodate the volume change during the stripping/plating of Li and facilitate more efficient electron transport, while silicon nanowires improve the wettability of the carbon host to liquefied Li and render uniform Li deposition on the surface of the composite electrode. The as-prepared C/SiNW/Li composite anode exhibits enhanced cycling stability with a low hysteresis of 40 mV for more than 200 h and a better rate tolerance even at a current density of up to 5 mA cm-2. When coupling with the LiNi0.5Mn1.5O4 cathode, the full cells using the C/SiNW/Li composite anode demonstrate a remarkable electrochemical performance with an exceptional rate performance of up to 10 C and stable long-term cycling (the capacity retention of 62% at a 5 C rate over 2000 cycles), which is much higher than the cells with pure Li anode. This work provides a universal strategy to fabricate the flexible and stable carbon-based Li metal anode toward high-energy-density batteries.