A Tailored Adhesive-Conductive Interlayer for Interface Stabilization of Large-Scale Lithium Metal Powder Electrodes for High-Energy-Density Batteries

Abstract

To address the limitations in thickness and width of lithium (Li) metal electrodes produced through traditional extrusion and pressing processes, a slurry-based coating method utilizing Li metal powder (LMP) is investigated, enabling the fabrication of ultra-thin and broad-width Li electrodes by simply tuning the coating conditions. Despite these advancements, LMP electrodes face critical challenges, including delamination of the LMP composite layer from the Cu current collector (CC) due to electrolyte infiltration at the interface and degradation of interfacial connectivity during charging/discharging cycles. To mitigate these issues, an adhesive-conductive polymer (AC-polymer) interlayer composed of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(styrene sulfonate-co-acrylic acid) (P(SS-co-AA) is introduced between the LMP composite layer and the Cu CC to improve interfacial stability. The incorporation of the AC-polymer interlayer significantly reduced the Li stripping overpotential from 89.8 to 35.8mV (a 60% decrease) and enhanced cycling stability, achieving 91% capacity retention at a 4mA cm−2 discharging rate after 150 cycles, even in a carbonate-based electrolyte. The successful fabrication of a 300mm-wide and 20µm-thick slurry-coated AC-LMP electrode represents a notable advancement in the development of Li metal batteries.