Controllable TiO coating on the nickel-rich layered cathode through TiCl hydrolysis fluidized bed chemical vapor deposition.

Surface coating of metal oxides is an effective approach for enhancing the capacity retention of a nickel-rich layered cathode. Current conventional coating techniques including wet chemistry methods and atomic layer deposition are restricted by the difficulty in perfectly balancing the coating quality and scale-up production. Herein, a highly efficient TiO coating route through fluidized bed chemical vapor deposition (FBCVD) was proposed to enable scalable and high yield synthesis of a TiO coated nickel-rich cathode. The technological parameters including coating time and TiCl supply rate were systematically studied, and thus a utility TiO deposition rate model was deduced, promoting the controllable TiO coating. The FBCVD TiO deposition mechanism was fundamentally analyzed based on the TiCl hydrolysis principle. The amorphous and uniform TiO coating layer is compactly attached on the particle surface, forming a classical core-shell structure. Electrochemical evaluations reveal that the TiO coating by FBCVD route indeed improves the capacity retention from 89.08% to 95.89% after 50 cycles.