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

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 NMC₈₁₁ 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.