Charged Insulating Skeleton-Enabled Deep Deposition and Robust Interface for Stable Lithium Metal Anodes.

Abstract

Conductive 3D collectors for lithium metal anodes always lead to the direct deposition of lithium on top of the skeleton, which contributes to aggressive volume change and an unstable interface layer. Herein, we design a three-dimensional collector composed of an insulating glass fiber skeleton and conductive copper substrate (NGF@Cu) to guide a bottom-up deep deposition of lithium metal. This composite structure with abundant pores realizes a directed ion-electron path and deep lithium deposition, fully harnessing its internal space to accommodate lithium. After modification with amino silane, the positively charged insulating skeletons show a regulated distribution of anions and rapid transport of Li ions in the electrolyte and lead to the formation of robust LiF-rich SEI layers, thereby inhibiting the growth of dendrites and the accumulation of dead lithium. Consequently, symmetrical batteries assembled with charged glass fiber/copper collectors exhibit a long lifespan of over 1300 h, while full batteries with NCM811 cathodes exhibit a stable cycling performance of over 300 cycles at 0.5 C and good capacity retention at high rates. The fabrication of charged insulating 3D collectors provides inspiration for metal electrodes with high energy density and reversibility.