Reactivating Dead Li by Shuttle Effect for High-Performance Anode-Free Li Metal Batteries

Anode-free Li metal batteries are considered the ultimate configuration for next-generation high energy-density Li-based batteries due to the elimination of excess Li metal. However, the limited Li source aggravates issues such as dendrite growth and "dead"Li formation. Any Li loss caused by the SEI formation and dead Li has a great influence on the performance of the full cell. Here, we introduce LiI with shuttle effect to suppress the Li dendrites and reactivate the dead Li in the anode-free LiFePO4 (LFP) |Cu full cells. During cycling, the iodine transforms between I- and I3-, and a chemical reactions occur spontaneously between I3- and Li dendrites or dead Li. The generated Li+ in the electrolyte remains active in the following cycling. The anode-free LFP|Cu cells deliver an initial discharge capacity of 139 mAh g-1 and maintain capacities of 100 mAh g-1 with a capacity retention of 72% after 100 cycles. Both the anode-free LFP|Cu coin cells and pouch cells with LiI additive show much-improved performances. This work provides a new strategy for high-performance anode-free Li metal batteries.