Realizing ultrafast Li-ion transport through electronegative nanochannels for high-rate lithium metal battery

Fast charging of lithium metal battery (LMB) is challenged by the sluggish Li+ diffusion in liquid electrolyte, resulting in excessive lithium dendrites growth issue. Towards overcoming this problem, here, we propose and demonstrate a new strategy for ultrafast Li+ transport in liquid LMB based on electronegative nanochannels (EN) in the functional separator. Experimental and computational results demonstrate that Li+ prefers to stay on the inner surface of the EN, with Grotthuss-like multiple ion collaborative transport rather than classical isolated ion random jumping, leading to ultrafast Li+ transport. As a result, the EN separator delivers a superior high Li+ conductivity (∼1 mS cm−1), and effectively stabilizes the lithium metal anode for 2000 h at a high current density of 5 mA cm−2. The EN separator significantly improves the rate performance of the LMB (Li||LiFePO4), whose discharge capacity reaches more than 90 mAh g−1 at a high rate of 10 C, with a retention rate of up to 73.9% after 100 cycles, much higher than commercial polyolefin separators. These results demonstrate the critical role of the EN separator in enabling ultrafast Li+ transport and boosting both performance and stability in high-rate LMBs, pointing the way to further rational developments in the area.