Dual‐functional Stacked Polymer Fibers for Stable Lithium Metal Batteries in Carbonate‐based Electrolytes

Lithium (Li) metal has long been thought to be an ideal anode material for high-energy-density Li metal batteries (LMBs). Nonetheless, a variety of safety risks and short cycle life due to uncontrollable Li dendrite growth limit its practical application. Here, a novel polymer-based 3D host composed of stacked polymer fibers (SPF) is purposefully designed using a simple electrospinning method to achieve dual-functional properties that endow bottom-up Li filling and morphologically regulate Li metal deposition over the host structure. As a result, the SPF allows for uniform Li-ion flux in the electrode, leading to densely packed Li deposition and further stable cycling in conventional carbonate-based electrolytes. Besides, a full cell paired with LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode results in a high-energy-density battery with a low negative/positive capacity ratio and a wide operating temperature range. This work presents a rational design for improving the stability and safety of Li metal anodes in conventional carbonate-based electrolytes for advanced LMBs.