Electrical Conductivity Gradient Based on Heterofibrous Scaffolds for Stable Lithium-Metal Batteries

The inability to guide the nucleation locations of electrochemically deposited Li has long been considered the main factor limiting the utilization of high-energy-density Li-metal batteries. In this study, an electrical conductivity gradient interfacial host comprising 1D high conductivity copper nanowires and nanocellulose insulating layers is used in stable Li-metal anodes. The conductivity gradient system guides the nucleation sites of Li-metal to be directed during electrochemical plating. Additionally, the controlled parameter of the intermediate layer affects the highly stable Li-metal plating. The electrochemical behavior is confirmed through experiments associated with the COMSOL Multiphysics simulation data. The distributed Li-ion reaction flux resulting from the controlled electrical conductivity enables stable cycling for more than 250 cycles at 1 mA cm⁻². The gradient system effectively suppresses dendrite growth even at a high current density of 5 mA cm⁻² and ensures Li plating and stripping with ultra-long-term stability. To demonstrate the high-energy-density full-cell application of the developed anode, it is paired with the LiNi_0.8Co_0.1Mn_0.1O₂ cathode. The cells demonstrate a high capacity retention of 90% with an extremely high Coulombic efficiency of 99.8% over 100 cycles. These results shed light on the formidable challenges involved in exploiting the engineering aspects of high-energy-density Li-metal batteries.