Roll‐To‐Roll Fabrication of Zero‐Volume‐Expansion Lithium‐Composite Anodes to Realize High‐Energy‐Density Flexible and Stable Lithium‐Metal Batteries

Abstract The lithium (Li)‐metal anode offers a promising solution for high‐energy‐density lithium‐metal batteries (LMBs). However, the significant volume expansion of the Li metal during charging results in poor cycling stability as a result of the dendritic deposition and broken solid electrolyte interphase. Herein, a facile one‐step roll‐to‐roll fabrication of a zero‐volume‐expansion Li‐metal‐composite anode (zeroVE‐Li) is proposed to realize high‐energy‐density LMBs with outstanding electrochemical and mechanical stability. The zeroVE‐Li possesses a sandwich‐like trilayer structure, which consists of an upper electron‐insulating layer and a bottom lithiophilic layer that synergistically guides the Li deposition from the bottom up, and a middle porous layer that eliminates volume expansion. This sandwich structure eliminates dendrite formation, prevents volume change during cycling, and provides outstanding flexibility to the Li‐metal anode even at a practical areal capacity over 3.0 mAh cm −2 . Pairing zeroVE‐Li with a commercial NMC 811 or LCO cathode, flexible LMBs that offer a record‐breaking figure of merit (FOM, 45.6), large whole‐cell energy density (375 Wh L −1 , based on the volume of the anode, separator, cathode, and package), high‐capacity retention (> 99.8% per cycle), and remarkable mechanical robustness under practical conditions are demonstrated.