In Situ Grown n‐Type Conducting Polymer Interface Enabling High‐Performance Lithium‐Ion Batteries With Enhanced Capacity, Fast Rate and Low‐Temperature Operation

Persistent popularity of electronic devices has resulted in increased demands for high energy density, charge/discharge rates, and stability of lithium‐ion batteries (LIBs). Lithium iron phosphate (LiFePO 4 , LFP) is a prevalent commercial cathode, but its slow Li + redox kinetics and poor conductivity severely limit performance. Herein, we introduce the recently developed n‐type conducting polymer poly(benzodifurandione) (PBFDO) for the interfacial modification which not only maintains electrode conductivity but also demonstrates lithium‐ion redox activity. In addition, when compared to post‐deposition directly utilizing conducting polymer solutions, the in situ formed n‐type conducting polymer interface on LFP demonstrates superior cycling performance and rate capability. This achieves a specific capacity of 194 mAh g −1 at 1C and maintains 92 mAh g −1 at the ultra‐high rate of 50C. The improved ionic–electronic transport properties also significantly enhance the low‐temperature performance, achieving remarkable capacity retention and rate capability (93 mAh g −1 at 5C) at −20°C. Moreover, large‐size pouch cells were fabricated, which exhibit enhanced rate performance (128 mAh g −1 at 5C) at room temperature. This study presents an effective approach for enhancing the energy density and rate performance of LIBs, pushing forward the development of next‐generation energy storage systems.