Trapping Lithium into Hollow Silica Microspheres with\na Carbon Nanotube Core for Dendrite-Free Lithium Metal Anodes

Abstract

Li\nmetal anodes, which have attracted much attention for their\nhigh specific capacity and low redox potential, face a great challenge\nin realizing their practical application. The fatal issue of dendrite\nformation gives rise to internal short circuit and safety hazards\nand needs to be addressed. Here we propose a rational strategy of\ntrapping Li within microcages to confine the deposition morphology\nand suppress dendrite growth. Microcages with a carbon nanotube core\nand porous silica sheath were prepared and proved to be effective\nfor controlling the electrodeposition behavior. In addition, the insulative\ncoating layer prevents concentrated electron flow and decreases the\npossibility of “hot spots” formation. Because of the\nLi trapper and uniform electron distribution, the electrode with delicate\nstructure exhibits a dendrite-free morphology after plating 2 mA h\ncm^–2 of Li. As the dendrite growth is suppressed,\nthe as-obtained electrode maintains a high plating/stripping efficiency\nof 99% over 200 cycles. This work delivers new insights into the design\nof rational Li metal anodes and hastens the practical application\nof Li metal batteries.