Interface Transformation and Optimization Mechanisms of Prelithiated Graphite Anodes via a Roll-to-Roll Process with Ultrathin Lithium Strips

Prelithiation is crucial for improving the initial Coulombic efficiency (ICE), energy density, and cycle life of lithium-ion batteries (LIBs). The roll-to-roll anode prelithiation technology using ultrathin lithium strips shows great potential for industrial production. However, its optimization mechanisms for battery performance enhancement are still unclear. This work develops a roll-to-roll Li strip prelithiated graphite anode and explores its performance optimization mechanisms by revealing transformation behaviors. In such an anode, the preimplanted active lithium is conducive to forming the reversible LiC₁₂ phase and the inorganic compound-rich solid electrolyte interphase (SEI), effectively compensating lithium loss and optimizing interfacial ion transport. More impressively, it promotes the homogenization of graphite defects and SEI, thereby suppressing interfacial electrolyte consumption and optimizing practical performance. As a result, this approach effectively improves the ICE, rate performance, and cycle life of the LIBs, enabling impressive performance with a 0.8 Ah Gr||LFP pouch cell cycled for over 2000 cycles at 1C without capacity fade. This work paves a new way for future industrial application of roll-to-roll anode prelithiation in high-energy-density, long-life LIBs.