Entrapping lithium deposition in lithiophilic reservoir constructed by vertically aligned ZnO nanosheets for dendrite-free Li metal anodes

Highlights: • ZnO nanosheets vertically grown on Ni foam as dendrite-free Li metal host. • ZnO nanosheets induce homogeneous Li deposition under high areal capacity. • Long cycle life in symmetric cells under high current density is achieved. -- Abstract: The safety issue and poor stability induced by dendrite growth and volume change present major barriers to the practical application of lithium-metal anode for next-generation high-energy-density batteries. Herein, we propose vertically aligned ZnO nanosheets derived from zinc-based MOF grown on Ni foam (LZNF) as a lithiophilic porous scaffold to mitigate these problems. The interspace between the cross-linked ZnO nanosheets as the lithiophilic reservoir enables homogenous plating/stripping of Li at a high deposition capacity of 15 mAh cm^-2, which is difficult to realize on Ni foam substrate decorated with normal ZnO particles. The integration of vertically aligned ZnO nanosheets and 3D conductive Ni foam can not only induce dendrite-free lithium deposition with reduced current density but also alleviate the volume fluctuations of lithium. Consequently, a high Coulombic efficiency in LZNF/Li half-cell (98.5% for 150 cycles at 1 mA cm^-2) and enhanced cycling stability of a symmetric LZNF@Li/LZNF@Li cell (5 mA cm^-2 for 250 cycles) with a small voltage hysteresis (45 mV) can be achieved. Our investigation shows that LZNF can serve as a promising multi-functional 3D host for dendrite-free Li metal anodes.