Flame retardant polymer current collector for safer and higher energy density lithium-metal batteries

Energy density and safety are two crucial parameters when evaluating lithium-metal batteries (LMBs). Herein, we present an ultralight polymer-based current collector, incorporating flame-retardant materials, designed specifically for thin lithium-metal anodes. Compared to the traditional copper current collector (8.96 mg cm-2 , 10 mu m thick), the polymer-based current collector (12 mu m thick) has a significantly lower areal density of 1.41 mg cm-2 , i.e., only one-sixth of the copper collector, thus enabling substantially higher energy densities. Accordingly, when employed in Li||NMC622 full-cells, the polymer-based current collector enables a specific energy of 449 Wh kg-1, representing a notable improvement of about 14.5% compared to cells employing a classic copper current collector. The inclusion of Al(OH)3 as a flame retardant into the current collector suppresses flammability and, thereby, significantly improves the safety of the resulting LMBs. (c) 2025 The Authors. Published by Published by Elsevier B.V. and Science Press on behalf of Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).