In Situ Grown n-Type Conducting Polymer Interface Enabling High-Performance Lithium-Ion Batteries With Enhanced...

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 (LiFePO₄, 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.