Conductivity Gradient Lithium Hosts based on Hetero-fibrous Scaffolds for Lithium-Metal Batteries = 리튬 금속 전지를 위한 이종섬유 기반의 전자전도도 그래디언트 리튬 호스트

다국어 초록 (Multilingual Abstract)

Metallic lithium (Li) have attracted considerable attention owing to its high theoretical capacity (3860 mAh g-1) as a promising anode candidate for next-generation battery. However, uneven plating/stripping behaviors of Li metal leads to severe safety issues and poor cycling performance due to formation of dendritic Li, seriously impeding the practical Li metal-based batteries. Here, we demonstrate a newly designed Li metal host (Li host) based on hetero-fibrous scaffold composed of one-dimensional (1D) electronic conductor (copper nanowire, CuNW) and electronic insulator (cellulose nanofiber, CNF) with electronic conductivity gradient structure. The electronic conductivity gradient architecture in the new scaffold offers stable Li plating/stripping behaviors which form preferential and uniformly dense Li deposition on the bottom layer with high electronic conductivity and suppression of Li dendritic growth on top surface of non-conductive top layer. Additionally, the middle layer which has well-tailored electronic conductivity enable effectively suppression dead Li formed from bottom layer and support to enhance actualization of long-term cyclability. These featured structural characteristics of Li host with electronic conductivity gradient achieve high Li utilization (>96% coulombic efficiency) and superior cycling stability at the current density of 1 mA cm-2 over 250 cycles. The resultant of NCM811||Li@host full-cell shows excellent cycling performance and structural stability of anode, thus demonstrating proper as Li host for high-energy density Li metal batteries.