Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast‐Charging Lithium‐Ion Batteries

Abstract The fast‐charging capability of rechargeable batteries is greatly limited by the sluggish ion transport kinetics in anode materials. Here we develop an iodized polyacrylonitrile (I‐PAN) anode that can boost the bulk/interphase lithium (Li)‐ion diffusion kinetics and accelerate Li‐ion desolvation process to realize high‐performance fast‐charging Li‐ion batteries. The iodine immobilized in I‐PAN framework expands ion transport channels, compresses the electric double layer, and changes the inner Helmholtz plane to form LiF/LiI‐rich solid electrolyte interphase layer. The dissolved iodine ions in the electrolyte self‐induced by the interfacial nucleophilic substitution of PF 6 − not only promote the Li‐ion desolvation process, but also reuse the plated/dead Li formed on the anode under fast‐charging conditions. Consequently, the I‐PAN anode exhibits a high capacity of 228.5 mAh g −1 (39 % of capacity at 0.5 A g −1 delivered in 18 seconds) and negligible capacity decay for 10000 cycles at 20 A g −1 . The I‐PAN||LiNi 0.8 Co 0.1 Mn 0.1 O 2 full cell shows excellent fast‐charging performance with attractive capacities and negligible capacity decay for 1000 cycles at extremely high rates of 5 C and 10 C (1 C=180 mA g −1 ). We also demonstrate high‐performance fast‐charging sodium‐ion batteries using I‐PAN anodes.