Catalytic Strategies Enabled Rapid Formation of Homogeneous and Mechanically Robust Inorganic-Rich Cathode Electrolyte Interface for High-Rate and High-Stability Lithium-Ion Batteries

Abstract

Lithium iron phosphate (LFP) cathode is renowned for high thermal stability and safety, making them a popular choice for lithium-ion batteries. Nevertheless, on one hand, the fast charge/discharge capability is fundamentally constrained by low electrical conductivity and anisotropic nature of sluggish lithium ion (Li⁺) diffusion. On the other hand, the interface and internal structural degradation occurs when subjected to high-rate condition. Herein, a multifunctional boron-doping graphene/lithium carbonate (BG/LCO) nanointerfacial layer on surface of commercial LiFePO₄ particles is designed, in which the BG layer catalyzes the rapid reaction of Li₂CO₃-LiPF₆ for homogeneous and mechanically robust inorganic LiF-rich structure across the cathode-electrolyte interphase (CEI), forms a conductive network to significantly enhance both electron and Li⁺ transport, and strengthens the FeO bonding to minimize both Fe loss and the formation of Fe-Li antisite defects. Correspondingly, the modified LFP cathode achieves a high capability of 113.2 mAh g⁻¹ at 10 C and extraordinary cyclic stability with 88.0% capacity retention over 1000 cycles as compared to the pristine LFP cathode with a capacity of only 94.0 mAh g⁻¹ and 64.6% capacity retention. It also exhibits great enhancements of 20.1% and 3.7% at higher-rate condition (room temperature/15 C) and the low temperature condition (−10 °C/1 C), respectively.