Lithium Niobate Coatings on Lithium Iron Phosphate Cathode Materials for Application in Lithium Ion Batteries

There remains a need to enhance existing cathode materials in lithium ion batteries (LIBs). For example, lithium iron phosphate (LFP) is hindered by low electrical conductivity and slow lithium ion diffusion. While carbon coatings improve LFP performance, alternative materials with higher ionic conductivities have not been thoroughly explored. In this study, we present a method to synthesize a patchwork-type lithium niobate (LiNbO 3 ) coating on LFP particles. LiNbO 3 coatings were fabricated using solvothermal methods to enhance the LFP performance. Electron microscopy and X-ray spectroscopy confirmed the successful deposition of a ∼10 nm thick layer of LiNbO 3 onto the LFP surfaces. The effects of this coating on LFP performance were evaluated through galvanostatic charge-discharge tests. Notably, carbon-coated LFP particles with a 1% w/w LiNbO 3 coating exhibited a specific discharge capacity of 146 mAh g −1 at a 0.1 C rate and retained ∼98% of their capacity after 300 cycles at a 1 C rate. Additionally, cyclic voltammetry and current interruption techniques were employed to assess lithium diffusion coefficients before and after 300+ charge-discharge cycles. The results demonstrate that the LiNbO 3 coating significantly enhanced lithium ion transport by stabilizing areas of the LFP particles with thin or discontinuous carbon coatings, improving performance even after extensive cycling.